{"id":"CVE-2026-43407","state":"PUBLISHED","title":"libceph: Fix potential out-of-bounds access in ceph_handle_auth_reply()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: Fix potential out-of-bounds access in ceph_handle_auth_reply()\n\nThis patch fixes an out-of-bounds access in ceph_handle_auth_reply()\nthat can be triggered by a message of type CEPH_MSG_AUTH_REPLY. In\nceph_handle_auth_reply(), the value of the payload_len field of such a\nmessage is stored in a variable of type int. A value greater than\nINT_MAX leads to an integer overflow and is interpreted as a negative\nvalue. This leads to decrementing the pointer address by this value and\nsubsequently accessing it because ceph_decode_need() only checks that\nthe memory access does not exceed the end address of the allocation.\n\nThis patch fixes the issue by changing the data type of payload_len to\nu32. Additionally, the data type of result_msg_len is changed to u32,\nas it is also a variable holding a non-negative length.\n\nAlso, an additional layer of sanity checks is introduced, ensuring that\ndirectly after reading it from the message, payload_len and\nresult_msg_len are not greater than the overall segment length.\n\nBUG: KASAN: slab-out-of-bounds in ceph_handle_auth_reply+0x642/0x7a0 [libceph]\nRead of size 4 at addr ffff88811404df14 by task kworker/20:1/262\n\nCPU: 20 UID: 0 PID: 262 Comm: kworker/20:1 Not tainted 6.19.2 #5 PREEMPT(voluntary)\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\nWorkqueue: ceph-msgr ceph_con_workfn [libceph]\nCall Trace:\n <TASK>\n dump_stack_lvl+0x76/0xa0\n print_report+0xd1/0x620\n ? __pfx__raw_spin_lock_irqsave+0x10/0x10\n ? kasan_complete_mode_report_info+0x72/0x210\n kasan_report+0xe7/0x130\n ? ceph_handle_auth_reply+0x642/0x7a0 [libceph]\n ? ceph_handle_auth_reply+0x642/0x7a0 [libceph]\n __asan_report_load_n_noabort+0xf/0x20\n ceph_handle_auth_reply+0x642/0x7a0 [libceph]\n mon_dispatch+0x973/0x23d0 [libceph]\n ? apparmor_socket_recvmsg+0x6b/0xa0\n ? __pfx_mon_dispatch+0x10/0x10 [libceph]\n ? __kasan_check_write+0x14/0x30i\n ? mutex_unlock+0x7f/0xd0\n ? __pfx_mutex_unlock+0x10/0x10\n ? __pfx_do_recvmsg+0x10/0x10 [libceph]\n ceph_con_process_message+0x1f1/0x650 [libceph]\n process_message+0x1e/0x450 [libceph]\n ceph_con_v2_try_read+0x2e48/0x6c80 [libceph]\n ? __pfx_ceph_con_v2_try_read+0x10/0x10 [libceph]\n ? save_fpregs_to_fpstate+0xb0/0x230\n ? raw_spin_rq_unlock+0x17/0xa0\n ? finish_task_switch.isra.0+0x13b/0x760\n ? __switch_to+0x385/0xda0\n ? __kasan_check_write+0x14/0x30\n ? mutex_lock+0x8d/0xe0\n ? __pfx_mutex_lock+0x10/0x10\n ceph_con_workfn+0x248/0x10c0 [libceph]\n process_one_work+0x629/0xf80\n ? __kasan_check_write+0x14/0x30\n worker_thread+0x87f/0x1570\n ? __pfx__raw_spin_lock_irqsave+0x10/0x10\n ? __pfx_try_to_wake_up+0x10/0x10\n ? kasan_print_address_stack_frame+0x1f7/0x280\n ? __pfx_worker_thread+0x10/0x10\n kthread+0x396/0x830\n ? __pfx__raw_spin_lock_irq+0x10/0x10\n ? __pfx_kthread+0x10/0x10\n ? __kasan_check_write+0x14/0x30\n ? recalc_sigpending+0x180/0x210\n ? __pfx_kthread+0x10/0x10\n ret_from_fork+0x3f7/0x610\n ? __pfx_ret_from_fork+0x10/0x10\n ? __switch_to+0x385/0xda0\n ? __pfx_kthread+0x10/0x10\n ret_from_fork_asm+0x1a/0x30\n </TASK>\n\n[ idryomov: replace if statements with ceph_decode_need() for\n  payload_len and result_msg_len ]","publishedAt":"2026-05-08T14:21:46.927Z","updatedAt":"2026-10-19T19:26:36.220Z","severity":{"score":9.1,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc","status":"affected","lessThan":"ea080b21092590122c3f971cf588932cdbf47847","versionType":"git"},{"version":"4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc","status":"affected","lessThan":"edc678e5cd11730a2834b43071d8923f05bc334d","versionType":"git"},{"version":"4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc","status":"affected","lessThan":"6cee34d6669fe176b4259131adb1a145c939b472","versionType":"git"},{"version":"4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc","status":"affected","lessThan":"8bb87547e92dcf0928ed763c60e0ac8d733c3656","versionType":"git"},{"version":"4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc","status":"affected","lessThan":"ed024d2f4c79c0eb2464df0fb640610ac301f9a0","versionType":"git"},{"version":"4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc","status":"affected","lessThan":"f9da5c1bbac5c8e33259fe00ed7347438fffa969","versionType":"git"},{"version":"4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc","status":"affected","lessThan":"9f9e2297f45fc2d2524eb104c289d69ddef95665","versionType":"git"},{"version":"4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc","status":"affected","lessThan":"b282c43ed156ae15ea76748fc15cd5c39dc9ab72","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ceph/auth.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.34","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.34","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":"6.1.167","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.130","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.78","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.19","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.9","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/ceph/auth.c"]}],"references":["https://git.kernel.org/stable/c/ea080b21092590122c3f971cf588932cdbf47847","https://git.kernel.org/stable/c/edc678e5cd11730a2834b43071d8923f05bc334d","https://git.kernel.org/stable/c/6cee34d6669fe176b4259131adb1a145c939b472","https://git.kernel.org/stable/c/8bb87547e92dcf0928ed763c60e0ac8d733c3656","https://git.kernel.org/stable/c/ed024d2f4c79c0eb2464df0fb640610ac301f9a0","https://git.kernel.org/stable/c/f9da5c1bbac5c8e33259fe00ed7347438fffa969","https://git.kernel.org/stable/c/9f9e2297f45fc2d2524eb104c289d69ddef95665","https://git.kernel.org/stable/c/b282c43ed156ae15ea76748fc15cd5c39dc9ab72"],"weaknesses":["CWE-190"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/43xxx/CVE-2026-43407.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-43407","state":"PUBLISHED","datePublished":"2026-05-08T14:21:46.927Z","dateUpdated":"2026-10-19T19:26:36.220Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-05-01T14:12:56.008Z"},"containers":{"cna":{"title":"libceph: Fix potential out-of-bounds access in ceph_handle_auth_reply()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: Fix potential out-of-bounds access in ceph_handle_auth_reply()\n\nThis patch fixes an out-of-bounds access in ceph_handle_auth_reply()\nthat can be triggered by a message of type CEPH_MSG_AUTH_REPLY. In\nceph_handle_auth_reply(), the value of the payload_len field of such a\nmessage is stored in a variable of type int. A value greater than\nINT_MAX leads to an integer overflow and is interpreted as a negative\nvalue. This leads to decrementing the pointer address by this value and\nsubsequently accessing it because ceph_decode_need() only checks that\nthe memory access does not exceed the end address of the allocation.\n\nThis patch fixes the issue by changing the data type of payload_len to\nu32. Additionally, the data type of result_msg_len is changed to u32,\nas it is also a variable holding a non-negative length.\n\nAlso, an additional layer of sanity checks is introduced, ensuring that\ndirectly after reading it from the message, payload_len and\nresult_msg_len are not greater than the overall segment length.\n\nBUG: KASAN: slab-out-of-bounds in ceph_handle_auth_reply+0x642/0x7a0 [libceph]\nRead of size 4 at addr ffff88811404df14 by task kworker/20:1/262\n\nCPU: 20 UID: 0 PID: 262 Comm: kworker/20:1 Not tainted 6.19.2 #5 PREEMPT(voluntary)\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\nWorkqueue: ceph-msgr ceph_con_workfn [libceph]\nCall Trace:\n <TASK>\n dump_stack_lvl+0x76/0xa0\n print_report+0xd1/0x620\n ? __pfx__raw_spin_lock_irqsave+0x10/0x10\n ? kasan_complete_mode_report_info+0x72/0x210\n kasan_report+0xe7/0x130\n ? ceph_handle_auth_reply+0x642/0x7a0 [libceph]\n ? ceph_handle_auth_reply+0x642/0x7a0 [libceph]\n __asan_report_load_n_noabort+0xf/0x20\n ceph_handle_auth_reply+0x642/0x7a0 [libceph]\n mon_dispatch+0x973/0x23d0 [libceph]\n ? apparmor_socket_recvmsg+0x6b/0xa0\n ? __pfx_mon_dispatch+0x10/0x10 [libceph]\n ? __kasan_check_write+0x14/0x30i\n ? mutex_unlock+0x7f/0xd0\n ? __pfx_mutex_unlock+0x10/0x10\n ? __pfx_do_recvmsg+0x10/0x10 [libceph]\n ceph_con_process_message+0x1f1/0x650 [libceph]\n process_message+0x1e/0x450 [libceph]\n ceph_con_v2_try_read+0x2e48/0x6c80 [libceph]\n ? __pfx_ceph_con_v2_try_read+0x10/0x10 [libceph]\n ? save_fpregs_to_fpstate+0xb0/0x230\n ? raw_spin_rq_unlock+0x17/0xa0\n ? finish_task_switch.isra.0+0x13b/0x760\n ? __switch_to+0x385/0xda0\n ? __kasan_check_write+0x14/0x30\n ? mutex_lock+0x8d/0xe0\n ? __pfx_mutex_lock+0x10/0x10\n ceph_con_workfn+0x248/0x10c0 [libceph]\n process_one_work+0x629/0xf80\n ? __kasan_check_write+0x14/0x30\n worker_thread+0x87f/0x1570\n ? __pfx__raw_spin_lock_irqsave+0x10/0x10\n ? __pfx_try_to_wake_up+0x10/0x10\n ? kasan_print_address_stack_frame+0x1f7/0x280\n ? __pfx_worker_thread+0x10/0x10\n kthread+0x396/0x830\n ? __pfx__raw_spin_lock_irq+0x10/0x10\n ? __pfx_kthread+0x10/0x10\n ? __kasan_check_write+0x14/0x30\n ? recalc_sigpending+0x180/0x210\n ? __pfx_kthread+0x10/0x10\n ret_from_fork+0x3f7/0x610\n ? __pfx_ret_from_fork+0x10/0x10\n ? __switch_to+0x385/0xda0\n ? __pfx_kthread+0x10/0x10\n ret_from_fork_asm+0x1a/0x30\n </TASK>\n\n[ idryomov: replace if statements with ceph_decode_need() for\n  payload_len and result_msg_len ]"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc","status":"affected","lessThan":"ea080b21092590122c3f971cf588932cdbf47847","versionType":"git"},{"version":"4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc","status":"affected","lessThan":"edc678e5cd11730a2834b43071d8923f05bc334d","versionType":"git"},{"version":"4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc","status":"affected","lessThan":"6cee34d6669fe176b4259131adb1a145c939b472","versionType":"git"},{"version":"4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc","status":"affected","lessThan":"8bb87547e92dcf0928ed763c60e0ac8d733c3656","versionType":"git"},{"version":"4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc","status":"affected","lessThan":"ed024d2f4c79c0eb2464df0fb640610ac301f9a0","versionType":"git"},{"version":"4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc","status":"affected","lessThan":"f9da5c1bbac5c8e33259fe00ed7347438fffa969","versionType":"git"},{"version":"4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc","status":"affected","lessThan":"9f9e2297f45fc2d2524eb104c289d69ddef95665","versionType":"git"},{"version":"4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc","status":"affected","lessThan":"b282c43ed156ae15ea76748fc15cd5c39dc9ab72","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ceph/auth.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.34","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.34","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":"6.1.167","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.130","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.78","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.19","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.9","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/ceph/auth.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/ea080b21092590122c3f971cf588932cdbf47847"},{"url":"https://git.kernel.org/stable/c/edc678e5cd11730a2834b43071d8923f05bc334d"},{"url":"https://git.kernel.org/stable/c/6cee34d6669fe176b4259131adb1a145c939b472"},{"url":"https://git.kernel.org/stable/c/8bb87547e92dcf0928ed763c60e0ac8d733c3656"},{"url":"https://git.kernel.org/stable/c/ed024d2f4c79c0eb2464df0fb640610ac301f9a0"},{"url":"https://git.kernel.org/stable/c/f9da5c1bbac5c8e33259fe00ed7347438fffa969"},{"url":"https://git.kernel.org/stable/c/9f9e2297f45fc2d2524eb104c289d69ddef95665"},{"url":"https://git.kernel.org/stable/c/b282c43ed156ae15ea76748fc15cd5c39dc9ab72"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","baseScore":9.1,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - The vulnerable `CEPH_MSG_AUTH_REPLY` is parsed from data received over a Ceph messenger TCP connection from a monitor peer. A malicious or compromised monitor, or an attacker in position to impersonate one, can supply the crafted network message remotely.\nAC:L - The trigger is a deterministic malformed length field in a single auth reply, with no race or unusual heap state required to reach the out-of-bounds read. The attacker controls the relevant message contents.\nPR:N - The vulnerable reply is processed by the kernel client from the network peer during monitor/auth session handling, before any attacker-controlled credentials are required on the target. No local account or target privileges are needed.\nUI:N - Once a Ceph client connects or reconnects to the monitor peer, the attacker can send the crafted reply without further victim action. This is server-to-client network input processing.\nS:U - The impact is within the Linux kernel/client security authority. It does not cross a hypervisor, IOMMU, or separate authorization scope boundary.\nC:H - The signed length overflow lets the attacker move the decode pointer before the message buffer and perform an out-of-bounds kernel memory read at an attacker-influenced offset. Although the immediate read is small, it is not confined to a fixed in-object field, so high confidentiality impact is the safer defensible choice.\nI:N - The bug is an out-of-bounds read caused by pointer underflow; the investigated path does not provide an out-of-bounds write or direct memory corruption primitive. The downstream auth handlers reject the inverted buffer range or ignore the payload.\nA:H - The commit includes a KASAN slab-out-of-bounds report in `ceph_handle_auth_reply()`, and attacker-controlled pointer underflow can fault or oops the kernel worker processing the connection. A malicious peer can repeat the malformed reply to disrupt affected clients."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:27:50.423Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34","versionEndExcluding":"5.10.253"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34","versionEndExcluding":"5.15.203"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34","versionEndExcluding":"6.1.167"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34","versionEndExcluding":"6.6.130"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34","versionEndExcluding":"6.12.78"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34","versionEndExcluding":"6.18.19"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34","versionEndExcluding":"6.19.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34","versionEndExcluding":"7.0"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-43407","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-10-16T15:17:11.997253Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-190","lang":"en","type":"CWE","description":"CWE-190 Integer Overflow or Wraparound"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T19:26:36.220Z"}}]}}}