{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-74631", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.922Z", "datePublished": "2026-08-22T15:32:12.334Z", "dateUpdated": "2026-10-16T19:06:03.774Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-25T05:40:55.722Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: smc: fix splice entry lifetime imbalance in smc_rx_splice\n\nsmc_rx_splice() passes pages to splice_to_pipe() before taking the\nreferences that cover the lifetime of each splice entry. In the\nVM-backed RMB path, splice_to_pipe() may drop unqueued entries through\nsmc_rx_spd_release(), while queued entries are released later via the\npipe buffer callback.\n\nThe old post-splice accounting also derives the number of queued VM pages\nfrom an offset mutated while building the descriptor, and a multi-page\nsplice pairs one sock_hold() with multiple sock_put() calls.\n\nTake the page and socket references for every candidate entry before\nsplice_to_pipe(), and drop the matching private state, page reference,\nand socket reference from smc_rx_spd_release() for entries that never\nget queued. This fixes a refcount imbalance that can underflow page\nrefcounts and trigger a use-after-free." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.4, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - smc_rx_splice is only reached via splice()/tee() on an SMC socket FD (syscall -> smc_splice_read -> smc_rx_recvmsg with pipe set); remote SMC peers can supply receive-buffer data but cannot execute the vulnerable splice path without a local process invoking splice on that socket.\nAC:L - The attacker controls splice length, can nearly fill the destination pipe to force splice_to_pipe to drop unqueued entries via smc_rx_spd_release, and can hit the multi-page VM-backed RMB path (smcr_buf_type or mixed-buffer vmalloc fallback); no timing race or external victim state is required.\nPR:N - Exploitation requires only completing an SMC session as a network peer to a victim that reads with splice (common zero-copy SMC pattern); no local account, capabilities, or namespace-admin rights on the victim host are needed beyond normal remote connectivity to the SMC service.\nUI:N - No per-exploit victim action is needed beyond an application already using splice on SMC receive; a malicious peer can deliver the receive data while the victim's normal automated splice path triggers the refcount imbalance without prompts or manual steps.\nS:U - Impact is kernel page refcount underflow and use-after-free within the same kernel security boundary, enabling privilege escalation or crash on the host; it does not cross VM, IOMMU, or sandbox authority boundaries.\nC:H - Refcount imbalance lets smc_rx_spd_release and pipe-buffer teardown free pages while still referenced, creating a UAF on RMB pages that can be turned into arbitrary kernel memory disclosure via heap reuse and spraying.\nI:H - Corrupted page lifetime and dangling pipe_buffer state enable heap metadata corruption and arbitrary kernel writes from the UAF primitive, supporting control-flow hijacking and local privilege escalation.\nA:H - Page refcount underflow and UAF during splice teardown can cause immediate kernel oops/panic; repeated splice from an SMC peer reliably triggers denial-of-service even when full exploitation is not attempted." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/smc/smc_rx.c" ], "versions": [ { "version": "9014db202cb764b8e14c53e7bacc81f9a1a2ba7f", "lessThan": "7ddc7af2ae7fc5a0c0635b245c0824c8b76de5cb", "status": "affected", "versionType": "git" }, { "version": "9014db202cb764b8e14c53e7bacc81f9a1a2ba7f", "lessThan": "07ad246529d136d5ef441d5ab4c305d132ff3090", "status": "affected", "versionType": "git" }, { "version": "9014db202cb764b8e14c53e7bacc81f9a1a2ba7f", "lessThan": "c841789e456ec6751342fa800639ce8e82ff0e6b", "status": "affected", "versionType": "git" }, { "version": "9014db202cb764b8e14c53e7bacc81f9a1a2ba7f", "lessThan": "af02c67ce654356c58db20a0bb2db33ace3b07a8", "status": "affected", "versionType": "git" }, { "version": "9014db202cb764b8e14c53e7bacc81f9a1a2ba7f", "lessThan": "ca8342b5fc24c249fdb998468f6a168b457c67e5", "status": "affected", "versionType": "git" }, { "version": "9014db202cb764b8e14c53e7bacc81f9a1a2ba7f", "lessThan": "0b7d54cedea5cb158e21925ae0c6c2f5c87ed2a0", "status": "affected", "versionType": "git" }, { "version": "9014db202cb764b8e14c53e7bacc81f9a1a2ba7f", "lessThan": "4515c78f4d9fd577270f012efeb062ea58b3682d", "status": "affected", "versionType": "git" }, { "version": "9014db202cb764b8e14c53e7bacc81f9a1a2ba7f", "lessThan": "5d9686af2976741bbd79b150d1c9e60b81e7f12e", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/smc/smc_rx.c" ], "versions": [ { "version": "4.18", "status": "affected" }, { "version": "0", "lessThan": "4.18", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.266", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.217", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.183", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.152", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.104", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.45", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.9", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.18", "versionEndExcluding": "5.10.266" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.18", "versionEndExcluding": "5.15.217" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.18", "versionEndExcluding": "6.1.183" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.18", "versionEndExcluding": "6.6.152" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.18", "versionEndExcluding": "6.12.104" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.18", "versionEndExcluding": "6.18.45" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.18", "versionEndExcluding": "7.1.9" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.18", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/7ddc7af2ae7fc5a0c0635b245c0824c8b76de5cb" }, { "url": "https://git.kernel.org/stable/c/07ad246529d136d5ef441d5ab4c305d132ff3090" }, { "url": "https://git.kernel.org/stable/c/c841789e456ec6751342fa800639ce8e82ff0e6b" }, { "url": "https://git.kernel.org/stable/c/af02c67ce654356c58db20a0bb2db33ace3b07a8" }, { "url": "https://git.kernel.org/stable/c/ca8342b5fc24c249fdb998468f6a168b457c67e5" }, { "url": "https://git.kernel.org/stable/c/0b7d54cedea5cb158e21925ae0c6c2f5c87ed2a0" }, { "url": "https://git.kernel.org/stable/c/4515c78f4d9fd577270f012efeb062ea58b3682d" }, { "url": "https://git.kernel.org/stable/c/5d9686af2976741bbd79b150d1c9e60b81e7f12e" } ], "title": "net: smc: fix splice entry lifetime imbalance in smc_rx_splice", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2026-74631", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "version": "2.0.3", "timestamp": "2026-10-16T19:03:01.320271Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:06:03.774Z" } } ] } }