{"id":"CVE-2026-80979","state":"PUBLISHED","title":"net/smc: unregister the connection before draining the rx tasklet","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: unregister the connection before draining the rx tasklet\n\nsmc_conn_free() calls smc_ism_unset_conn() only while the link group is\nstill on its device list, and never sets conn->killed.\nsmc_lgr_terminate_sched() unlinks the group immediately and defers killing\nits connections to a work item, so a connection freed in that window keeps\nits smcd->conn[] slot with both gates in smcd_handle_irq() open, and the\ndevice can re-arm the receive tasklet after tasklet_kill() has returned. On\nthe DMB-nocopy path the ghost send buffer is freed right after that drain,\nso the re-armed tasklet dereferences it.\n\nUnregister unconditionally and drain before the detach at both teardown\nsites, mirroring rmb_desc, which smc_buf_unuse() releases after the drain.\nClear conn->sndbuf_desc before freeing it as well, so a reader that samples\nthe pointer cannot get one that is already freed.","publishedAt":"2026-09-11T19:42:40.171Z","updatedAt":"2026-10-19T08:46:03.770Z","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":"21f6f41e82e59740e26e06e77bdf58dc7f6f08dd","status":"affected","lessThan":"b6b6ac713ee82b340a8e3be30b101bd2840deec4","versionType":"git"},{"version":"ae2be35cbed2c8385e890147ea321a3fcc3ca5fa","status":"affected","lessThan":"b4d540ac95cd35c6ebab6afb7eae2bcac7b277a5","versionType":"git"},{"version":"ae2be35cbed2c8385e890147ea321a3fcc3ca5fa","status":"affected","lessThan":"5bd8b764a610b6b6bc0c4d3d01652747f6e0b5c3","versionType":"git"},{"version":"ae2be35cbed2c8385e890147ea321a3fcc3ca5fa","status":"affected","lessThan":"b74d313567dfc1b7e56629ddbad04e728686f235","versionType":"git"},{"version":"ae2be35cbed2c8385e890147ea321a3fcc3ca5fa","status":"affected","lessThan":"36cdf5d48ca191dcd71c28cadbe0981b1d25318d","versionType":"git"},{"version":"6.6.66","status":"affected","lessThan":"6.6.157","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/smc/smc_core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.10","versionType":"semver"},{"version":"6.6.157","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.109","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.50","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.4","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","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_core.c"]}],"references":["https://git.kernel.org/stable/c/b6b6ac713ee82b340a8e3be30b101bd2840deec4","https://git.kernel.org/stable/c/b4d540ac95cd35c6ebab6afb7eae2bcac7b277a5","https://git.kernel.org/stable/c/5bd8b764a610b6b6bc0c4d3d01652747f6e0b5c3","https://git.kernel.org/stable/c/b74d313567dfc1b7e56629ddbad04e728686f235","https://git.kernel.org/stable/c/36cdf5d48ca191dcd71c28cadbe0981b1d25318d"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:07.220Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/80xxx/CVE-2026-80979.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-80979","state":"PUBLISHED","datePublished":"2026-09-11T19:42:40.171Z","dateUpdated":"2026-10-19T08:46:03.770Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-26T14:34:25.811Z"},"containers":{"cna":{"title":"net/smc: unregister the connection before draining the rx tasklet","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: unregister the connection before draining the rx tasklet\n\nsmc_conn_free() calls smc_ism_unset_conn() only while the link group is\nstill on its device list, and never sets conn->killed.\nsmc_lgr_terminate_sched() unlinks the group immediately and defers killing\nits connections to a work item, so a connection freed in that window keeps\nits smcd->conn[] slot with both gates in smcd_handle_irq() open, and the\ndevice can re-arm the receive tasklet after tasklet_kill() has returned. On\nthe DMB-nocopy path the ghost send buffer is freed right after that drain,\nso the re-armed tasklet dereferences it.\n\nUnregister unconditionally and drain before the detach at both teardown\nsites, mirroring rmb_desc, which smc_buf_unuse() releases after the drain.\nClear conn->sndbuf_desc before freeing it as well, so a reader that samples\nthe pointer cannot get one that is already freed."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"21f6f41e82e59740e26e06e77bdf58dc7f6f08dd","status":"affected","lessThan":"b6b6ac713ee82b340a8e3be30b101bd2840deec4","versionType":"git"},{"version":"ae2be35cbed2c8385e890147ea321a3fcc3ca5fa","status":"affected","lessThan":"b4d540ac95cd35c6ebab6afb7eae2bcac7b277a5","versionType":"git"},{"version":"ae2be35cbed2c8385e890147ea321a3fcc3ca5fa","status":"affected","lessThan":"5bd8b764a610b6b6bc0c4d3d01652747f6e0b5c3","versionType":"git"},{"version":"ae2be35cbed2c8385e890147ea321a3fcc3ca5fa","status":"affected","lessThan":"b74d313567dfc1b7e56629ddbad04e728686f235","versionType":"git"},{"version":"ae2be35cbed2c8385e890147ea321a3fcc3ca5fa","status":"affected","lessThan":"36cdf5d48ca191dcd71c28cadbe0981b1d25318d","versionType":"git"},{"version":"6.6.66","status":"affected","lessThan":"6.6.157","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/smc/smc_core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.10","versionType":"semver"},{"version":"6.6.157","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.109","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.50","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.4","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","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_core.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/b6b6ac713ee82b340a8e3be30b101bd2840deec4"},{"url":"https://git.kernel.org/stable/c/b4d540ac95cd35c6ebab6afb7eae2bcac7b277a5"},{"url":"https://git.kernel.org/stable/c/5bd8b764a610b6b6bc0c4d3d01652747f6e0b5c3"},{"url":"https://git.kernel.org/stable/c/b74d313567dfc1b7e56629ddbad04e728686f235"},{"url":"https://git.kernel.org/stable/c/36cdf5d48ca191dcd71c28cadbe0981b1d25318d"}],"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 UAF is on the SMC-D DMB-nocopy teardown path, which only loopback-ISM implements; that device accepts a peer only when the GID matches this host, so a local AF_SMC/IPPROTO_SMC pair reaches smc_conn_free()/smcd_handle_irq(), and a remote TCP/CLC peer cannot attach to that fabric.\nAC:L - The attacker owns both sockets and can send on one endpoint to arm smcd_handle_irq() while close() on the other runs smc_conn_free()/smc_conn_kill, which kfree sndbuf_desc before tasklet_kill; they control both sides of the race, so complexity is Low.\nPR:L - socket(AF_SMC) and IPPROTO_SMC listen/connect on ephemeral ports need no capabilities, and loopback-ISM is usable from a user network namespace, so only an unprivileged local account is required.\nUI:N - The attacker performs connect, send, and close on their own SMC sockets; no separate victim action such as mounting a filesystem or opening a file is required.\nS:U - The freed object is a kernel kmalloc smc_buf_desc processed by a tasklet in the same kernel; this is privilege escalation within one security authority, not a VM, IOMMU, or sandbox escape.\nC:H - smcd_cdc_rx_tsklet/smc_cdc_msg_recv_action dereference the freed ghost sndbuf_desc (including ->len); a slab use-after-free of a kmalloc object that the attacker can spray yields an arbitrary kernel read.\nI:H - The same tasklet continues into cursor updates and smc_tx_pending() which write through the recycled descriptor, so heap spraying the use-after-free provides an arbitrary kernel write and control-flow hijack primitive.\nA:H - Tasklet use of the freed smc_buf_desc oopses or panics the kernel even without a full exploit, causing a full system availability loss that the attacker can repeat."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T08:46:03.770Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.66","versionEndExcluding":"6.6.157"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.12.109"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.18.50"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"7.2.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}