{"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": "2026-08-25T05:40:55.722Z"}, "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"}}}}

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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/smc/smc_rx.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "7ddc7af2ae7fc5a0c0635b245c0824c8b76de5cb", "status": "affected", "version": "9014db202cb764b8e14c53e7bacc81f9a1a2ba7f", "versionType": "git"}, {"lessThan": "07ad246529d136d5ef441d5ab4c305d132ff3090", "status": "affected", "version": "9014db202cb764b8e14c53e7bacc81f9a1a2ba7f", "versionType": "git"}, {"lessThan": "c841789e456ec6751342fa800639ce8e82ff0e6b", "status": "affected", "version": "9014db202cb764b8e14c53e7bacc81f9a1a2ba7f", "versionType": "git"}, {"lessThan": "af02c67ce654356c58db20a0bb2db33ace3b07a8", "status": "affected", "version": "9014db202cb764b8e14c53e7bacc81f9a1a2ba7f", "versionType": "git"}, {"lessThan": "ca8342b5fc24c249fdb998468f6a168b457c67e5", "status": "affected", "version": "9014db202cb764b8e14c53e7bacc81f9a1a2ba7f", "versionType": "git"}, {"lessThan": "0b7d54cedea5cb158e21925ae0c6c2f5c87ed2a0", "status": "affected", "version": "9014db202cb764b8e14c53e7bacc81f9a1a2ba7f", "versionType": "git"}, {"lessThan": "4515c78f4d9fd577270f012efeb062ea58b3682d", "status": "affected", "version": "9014db202cb764b8e14c53e7bacc81f9a1a2ba7f", "versionType": "git"}, {"lessThan": "5d9686af2976741bbd79b150d1c9e60b81e7f12e", "status": "affected", "version": "9014db202cb764b8e14c53e7bacc81f9a1a2ba7f", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/smc/smc_rx.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "4.18"}, {"lessThan": "4.18", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "5.10.*", "status": "unaffected", "version": "5.10.266", "versionType": "semver"}, {"lessThanOrEqual": "5.15.*", "status": "unaffected", "version": "5.15.217", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.183", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.152", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.104", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.45", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.9", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.2", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "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."}], "id": "CVE-2026-74631", "lastModified": "2026-08-25T06:18:42.167", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 8.4, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 2.5, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-08-22T16:16:36.080", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/07ad246529d136d5ef441d5ab4c305d132ff3090"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/0b7d54cedea5cb158e21925ae0c6c2f5c87ed2a0"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/4515c78f4d9fd577270f012efeb062ea58b3682d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/5d9686af2976741bbd79b150d1c9e60b81e7f12e"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/7ddc7af2ae7fc5a0c0635b245c0824c8b76de5cb"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/af02c67ce654356c58db20a0bb2db33ace3b07a8"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/c841789e456ec6751342fa800639ce8e82ff0e6b"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/ca8342b5fc24c249fdb998468f6a168b457c67e5"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: net: smc: fix splice entry lifetime imbalance in smc_rx_splice", "id": "2521413", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2521413"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.0", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-911", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nnet: smc: fix splice entry lifetime imbalance in smc_rx_splice\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.\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.\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.", "A flaw was found in the Linux kernel's `smc_rx_splice` function within the net: smc component. This vulnerability arises from an imbalance in the lifetime management of splice entries, where page references are not properly handled before being passed to `splice_to_pipe()`. This can lead to a reference count underflow, resulting in a use-after-free condition. A successful exploitation of this flaw could potentially lead to arbitrary code execution or a denial of service."], "name": "CVE-2026-74631", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-08-22T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-74631\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-74631\nhttps://lore.kernel.org/linux-cve-announce/2026082221-CVE-2026-74631-4134@gregkh/T"], "threat_severity": "Moderate"}

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