{"id":"CVE-2026-31507","state":"PUBLISHED","title":"net/smc: fix double-free of smc_spd_priv when tee() duplicates splice pipe buffer","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: fix double-free of smc_spd_priv when tee() duplicates splice pipe buffer\n\nsmc_rx_splice() allocates one smc_spd_priv per pipe_buffer and stores\nthe pointer in pipe_buffer.private.  The pipe_buf_operations for these\nbuffers used .get = generic_pipe_buf_get, which only increments the page\nreference count when tee(2) duplicates a pipe buffer.  The smc_spd_priv\npointer itself was not handled, so after tee() both the original and the\ncloned pipe_buffer share the same smc_spd_priv *.\n\nWhen both pipes are subsequently released, smc_rx_pipe_buf_release() is\ncalled twice against the same object:\n\n  1st call: kfree(priv)  sock_put(sk)  smc_rx_update_cons()  [correct]\n  2nd call: kfree(priv)  sock_put(sk)  smc_rx_update_cons()  [UAF]\n\nKASAN reports a slab-use-after-free in smc_rx_pipe_buf_release(), which\nthen escalates to a NULL-pointer dereference and kernel panic via\nsmc_rx_update_consumer() when it chases the freed priv->smc pointer:\n\n  BUG: KASAN: slab-use-after-free in smc_rx_pipe_buf_release+0x78/0x2a0\n  Read of size 8 at addr ffff888004a45740 by task smc_splice_tee_/74\n  Call Trace:\n   <TASK>\n   dump_stack_lvl+0x53/0x70\n   print_report+0xce/0x650\n   kasan_report+0xc6/0x100\n   smc_rx_pipe_buf_release+0x78/0x2a0\n   free_pipe_info+0xd4/0x130\n   pipe_release+0x142/0x160\n   __fput+0x1c6/0x490\n   __x64_sys_close+0x4f/0x90\n   do_syscall_64+0xa6/0x1a0\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n   </TASK>\n\n  BUG: kernel NULL pointer dereference, address: 0000000000000020\n  RIP: 0010:smc_rx_update_consumer+0x8d/0x350\n  Call Trace:\n   <TASK>\n   smc_rx_pipe_buf_release+0x121/0x2a0\n   free_pipe_info+0xd4/0x130\n   pipe_release+0x142/0x160\n   __fput+0x1c6/0x490\n   __x64_sys_close+0x4f/0x90\n   do_syscall_64+0xa6/0x1a0\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n   </TASK>\n  Kernel panic - not syncing: Fatal exception\n\nBeyond the memory-safety problem, duplicating an SMC splice buffer is\nsemantically questionable: smc_rx_update_cons() would advance the\nconsumer cursor twice for the same data, corrupting receive-window\naccounting.  A refcount on smc_spd_priv could fix the double-free, but\nthe cursor-accounting issue would still need to be addressed separately.\n\nThe .get callback is invoked by both tee(2) and splice_pipe_to_pipe()\nfor partial transfers; both will now return -EFAULT.  Users who need\nto duplicate SMC socket data must use a copy-based read path.","publishedAt":"2026-04-22T13:54:25.910Z","updatedAt":"2026-10-19T18:45:54.233Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"9014db202cb764b8e14c53e7bacc81f9a1a2ba7f","status":"affected","lessThan":"7e8916f46c2f48607f907fd401590093753a6bc5","versionType":"git"},{"version":"9014db202cb764b8e14c53e7bacc81f9a1a2ba7f","status":"affected","lessThan":"ae5575e660410c8d2c5d38fb28a0f37aea945676","versionType":"git"},{"version":"9014db202cb764b8e14c53e7bacc81f9a1a2ba7f","status":"affected","lessThan":"98ba5cb274768146e25ffbfde47753652c1c20d3","versionType":"git"},{"version":"9014db202cb764b8e14c53e7bacc81f9a1a2ba7f","status":"affected","lessThan":"81acbd345d405994875d419d43b319fee0b9ad62","versionType":"git"},{"version":"9014db202cb764b8e14c53e7bacc81f9a1a2ba7f","status":"affected","lessThan":"7bcb974c771c863e8588cea0012ac204443a7126","versionType":"git"},{"version":"9014db202cb764b8e14c53e7bacc81f9a1a2ba7f","status":"affected","lessThan":"54c87a730157868543ebdfa0ecb21b4590ed23a5","versionType":"git"},{"version":"9014db202cb764b8e14c53e7bacc81f9a1a2ba7f","status":"affected","lessThan":"3cc76380fea749280c026f410af56a28aaac388a","versionType":"git"},{"version":"9014db202cb764b8e14c53e7bacc81f9a1a2ba7f","status":"affected","lessThan":"24dd586bb4cbba1889a50abe74143817a095c1c9","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/smc/smc_rx.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.18","versionType":"semver"},{"version":"5.10.253","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.203","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.168","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.131","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.80","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.21","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.11","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/smc/smc_rx.c"]}],"references":["https://git.kernel.org/stable/c/7e8916f46c2f48607f907fd401590093753a6bc5","https://git.kernel.org/stable/c/ae5575e660410c8d2c5d38fb28a0f37aea945676","https://git.kernel.org/stable/c/98ba5cb274768146e25ffbfde47753652c1c20d3","https://git.kernel.org/stable/c/81acbd345d405994875d419d43b319fee0b9ad62","https://git.kernel.org/stable/c/7bcb974c771c863e8588cea0012ac204443a7126","https://git.kernel.org/stable/c/54c87a730157868543ebdfa0ecb21b4590ed23a5","https://git.kernel.org/stable/c/3cc76380fea749280c026f410af56a28aaac388a","https://git.kernel.org/stable/c/24dd586bb4cbba1889a50abe74143817a095c1c9","https://cert-portal.siemens.com/productcert/html/ssa-082556.html","https://cert-portal.siemens.com/productcert/html/ssa-019113.html","https://cert-portal.siemens.com/productcert/html/ssa-457936.html"],"weaknesses":["CWE-415"],"ingestedAt":"2026-10-29T20:11:40.391Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/31xxx/CVE-2026-31507.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-31507","state":"PUBLISHED","datePublished":"2026-04-22T13:54:25.910Z","dateUpdated":"2026-10-19T18:45:54.233Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-03-09T15:48:24.106Z"},"containers":{"cna":{"title":"net/smc: fix double-free of smc_spd_priv when tee() duplicates splice pipe buffer","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: fix double-free of smc_spd_priv when tee() duplicates splice pipe buffer\n\nsmc_rx_splice() allocates one smc_spd_priv per pipe_buffer and stores\nthe pointer in pipe_buffer.private.  The pipe_buf_operations for these\nbuffers used .get = generic_pipe_buf_get, which only increments the page\nreference count when tee(2) duplicates a pipe buffer.  The smc_spd_priv\npointer itself was not handled, so after tee() both the original and the\ncloned pipe_buffer share the same smc_spd_priv *.\n\nWhen both pipes are subsequently released, smc_rx_pipe_buf_release() is\ncalled twice against the same object:\n\n  1st call: kfree(priv)  sock_put(sk)  smc_rx_update_cons()  [correct]\n  2nd call: kfree(priv)  sock_put(sk)  smc_rx_update_cons()  [UAF]\n\nKASAN reports a slab-use-after-free in smc_rx_pipe_buf_release(), which\nthen escalates to a NULL-pointer dereference and kernel panic via\nsmc_rx_update_consumer() when it chases the freed priv->smc pointer:\n\n  BUG: KASAN: slab-use-after-free in smc_rx_pipe_buf_release+0x78/0x2a0\n  Read of size 8 at addr ffff888004a45740 by task smc_splice_tee_/74\n  Call Trace:\n   <TASK>\n   dump_stack_lvl+0x53/0x70\n   print_report+0xce/0x650\n   kasan_report+0xc6/0x100\n   smc_rx_pipe_buf_release+0x78/0x2a0\n   free_pipe_info+0xd4/0x130\n   pipe_release+0x142/0x160\n   __fput+0x1c6/0x490\n   __x64_sys_close+0x4f/0x90\n   do_syscall_64+0xa6/0x1a0\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n   </TASK>\n\n  BUG: kernel NULL pointer dereference, address: 0000000000000020\n  RIP: 0010:smc_rx_update_consumer+0x8d/0x350\n  Call Trace:\n   <TASK>\n   smc_rx_pipe_buf_release+0x121/0x2a0\n   free_pipe_info+0xd4/0x130\n   pipe_release+0x142/0x160\n   __fput+0x1c6/0x490\n   __x64_sys_close+0x4f/0x90\n   do_syscall_64+0xa6/0x1a0\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n   </TASK>\n  Kernel panic - not syncing: Fatal exception\n\nBeyond the memory-safety problem, duplicating an SMC splice buffer is\nsemantically questionable: smc_rx_update_cons() would advance the\nconsumer cursor twice for the same data, corrupting receive-window\naccounting.  A refcount on smc_spd_priv could fix the double-free, but\nthe cursor-accounting issue would still need to be addressed separately.\n\nThe .get callback is invoked by both tee(2) and splice_pipe_to_pipe()\nfor partial transfers; both will now return -EFAULT.  Users who need\nto duplicate SMC socket data must use a copy-based read path."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"9014db202cb764b8e14c53e7bacc81f9a1a2ba7f","status":"affected","lessThan":"7e8916f46c2f48607f907fd401590093753a6bc5","versionType":"git"},{"version":"9014db202cb764b8e14c53e7bacc81f9a1a2ba7f","status":"affected","lessThan":"ae5575e660410c8d2c5d38fb28a0f37aea945676","versionType":"git"},{"version":"9014db202cb764b8e14c53e7bacc81f9a1a2ba7f","status":"affected","lessThan":"98ba5cb274768146e25ffbfde47753652c1c20d3","versionType":"git"},{"version":"9014db202cb764b8e14c53e7bacc81f9a1a2ba7f","status":"affected","lessThan":"81acbd345d405994875d419d43b319fee0b9ad62","versionType":"git"},{"version":"9014db202cb764b8e14c53e7bacc81f9a1a2ba7f","status":"affected","lessThan":"7bcb974c771c863e8588cea0012ac204443a7126","versionType":"git"},{"version":"9014db202cb764b8e14c53e7bacc81f9a1a2ba7f","status":"affected","lessThan":"54c87a730157868543ebdfa0ecb21b4590ed23a5","versionType":"git"},{"version":"9014db202cb764b8e14c53e7bacc81f9a1a2ba7f","status":"affected","lessThan":"3cc76380fea749280c026f410af56a28aaac388a","versionType":"git"},{"version":"9014db202cb764b8e14c53e7bacc81f9a1a2ba7f","status":"affected","lessThan":"24dd586bb4cbba1889a50abe74143817a095c1c9","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/smc/smc_rx.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.18","versionType":"semver"},{"version":"5.10.253","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.203","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.168","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.131","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.80","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.21","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.11","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/smc/smc_rx.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/7e8916f46c2f48607f907fd401590093753a6bc5"},{"url":"https://git.kernel.org/stable/c/ae5575e660410c8d2c5d38fb28a0f37aea945676"},{"url":"https://git.kernel.org/stable/c/98ba5cb274768146e25ffbfde47753652c1c20d3"},{"url":"https://git.kernel.org/stable/c/81acbd345d405994875d419d43b319fee0b9ad62"},{"url":"https://git.kernel.org/stable/c/7bcb974c771c863e8588cea0012ac204443a7126"},{"url":"https://git.kernel.org/stable/c/54c87a730157868543ebdfa0ecb21b4590ed23a5"},{"url":"https://git.kernel.org/stable/c/3cc76380fea749280c026f410af56a28aaac388a"},{"url":"https://git.kernel.org/stable/c/24dd586bb4cbba1889a50abe74143817a095c1c9"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The vulnerable path requires a local process to create or use an established non-fallback SMC socket, splice data from it into a pipe, and then duplicate that pipe buffer with tee(2) or partial pipe-to-pipe splice. A remote SMC peer can supply data, but cannot by itself invoke the required local splice/tee pipe-buffer operations.\nAC:L - There is no race or fragile timing requirement; once SMC data is available, the attacker-controlled syscall sequence deterministically creates two pipe buffers sharing the same smc_spd_priv. SMC-capable hardware/configuration is an affected deployment condition, not an exploitation race.\nPR:L - Creating SMC stream sockets and invoking splice(2), tee(2), pipe(2), and close(2) do not require CAP_NET_ADMIN or other elevated privileges. The attacker needs only basic local code execution.\nUI:N - No victim action is needed once the attacker has local execution; the attacker can perform the full syscall sequence and close both pipes. Any remote peer data needed for the SMC receive buffer can be generated by attacker-controlled endpoints in a plausible deployment.\nS:U - The vulnerability corrupts kernel memory in the same operating-system security authority as the vulnerable SMC/socket/pipe code. It is a standard kernel memory corruption issue, not a VM escape or cross-authority boundary bypass.\nC:H - The bug is a use-after-free/double-free of a heap object containing a kernel pointer and length, and the freed object is dereferenced on the second pipe-buffer release. Following kernel CVSS guidance, this memory corruption can support information disclosure primitives.\nI:H - The duplicate release can lead to allocator corruption and attacker-influenced dereferences through the freed smc_spd_priv contents. Following kernel CVSS guidance for UAF/double-free memory corruption, arbitrary write or control-flow compromise is a defensible impact.\nA:H - The reported failure includes KASAN slab-use-after-free followed by NULL pointer dereference and kernel panic in smc_rx_update_consumer(). Even without full exploitation, the sequence can crash the kernel."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:23:09.141Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.18","versionEndExcluding":"5.10.253"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.18","versionEndExcluding":"5.15.203"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.18","versionEndExcluding":"6.1.168"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.18","versionEndExcluding":"6.6.131"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.18","versionEndExcluding":"6.12.80"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.18","versionEndExcluding":"6.18.21"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.18","versionEndExcluding":"6.19.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.18","versionEndExcluding":"7.0"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"affected":[{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.6","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.5","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.7","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.6","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.5","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.7","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.6","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.5","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.7","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.6","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.5","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.7","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIPLUS S7-1500 CPU 1518-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.6","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIPLUS S7-1500 CPU 1518-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.5","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIPLUS S7-1500 CPU 1518-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.7","status":"affected","lessThan":"*","versionType":"custom"}]}],"references":[{"url":"https://cert-portal.siemens.com/productcert/html/ssa-082556.html"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-019113.html"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-457936.html"}],"providerMetadata":{"shortName":"siemens-SADP","orgId":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e","dateUpdated":"2026-10-15T01:16:46.107Z"},"x_adpType":"supplier"},{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-31507","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:10:23.030558Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-415","lang":"en","type":"CWE","description":"CWE-415 Double Free"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T18:45:54.233Z"}}]}}}