{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-23456", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-01-13T15:37:46.020Z", "datePublished": "2026-04-03T15:15:37.534Z", "dateUpdated": "2026-08-05T12:21:55.155Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:21:55.155Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack_h323: fix OOB read in decode_int() CONS case\n\nIn decode_int(), the CONS case calls get_bits(bs, 2) to read a length\nvalue, then calls get_uint(bs, len) without checking that len bytes\nremain in the buffer. The existing boundary check only validates the\n2 bits for get_bits(), not the subsequent 1-4 bytes that get_uint()\nreads. This allows a malformed H.323/RAS packet to cause a 1-4 byte\nslab-out-of-bounds read.\n\nAdd a boundary check for len bytes after get_bits() and before\nget_uint()." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H", "baseScore": 8.2, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - The vulnerable parser is reached by network-delivered H.323/RAS UDP traffic when the nf_conntrack_h323 RAS helper is active on a firewall/NAT gateway. A remote peer can supply the malformed packet payload that drives DecodeRasMessage() into decode_int().\nAC:L - The trigger is a deterministic malformed CONS integer where the 2-bit length claims 1-4 bytes that are not present. No race or attacker-external condition is required once the helper is attached to the flow.\nPR:N - The packet decoding path has no authentication or privilege check; it runs on received network traffic before any H.323 protocol-level trust decision. Helper configuration/loading may be administrative setup, but the attacker sending the malformed packet needs no privileges on the target.\nUI:N - Exploitation only requires sending crafted network traffic to a system processing H.323/RAS through conntrack. No victim user action is required.\nS:U - The impact is within the kernel/network filtering security authority of the affected system. There is no guest-to-host, sandbox, or separate authority boundary crossed.\nC:L - The bug is a bounded 1-4 byte slab out-of-bounds read from adjacent kernel memory. Because the read is strictly limited to a few bytes and not a broad arbitrary read primitive, confidentiality impact is limited.\nI:N - The flaw is an out-of-bounds read only; it does not write beyond bounds or corrupt kernel objects. The decoded value only affects existing H.323 conntrack timeout handling.\nA:H - A malformed unauthenticated packet can repeatedly trigger a slab out-of-bounds read in softirq packet processing, which can produce a KASAN/oops/panic on hardened or debug kernels. This is defensibly a high availability impact for affected deployments." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/netfilter/nf_conntrack_h323_asn1.c" ], "versions": [ { "version": "5e35941d990123f155b02d5663e51a24f816b6f3", "lessThan": "a2cd54b9348e485d338b3c132338a4410c99afaf", "status": "affected", "versionType": "git" }, { "version": "5e35941d990123f155b02d5663e51a24f816b6f3", "lessThan": "c95dc674ebf01ecfb40388b6facfc89b81fed3b7", "status": "affected", "versionType": "git" }, { "version": "5e35941d990123f155b02d5663e51a24f816b6f3", "lessThan": "41b417ff73a24b2c68134992cc44c88db27f482d", "status": "affected", "versionType": "git" }, { "version": "5e35941d990123f155b02d5663e51a24f816b6f3", "lessThan": "52235bf88159a1ef16434ab49e47e99c8a09ab20", "status": "affected", "versionType": "git" }, { "version": "5e35941d990123f155b02d5663e51a24f816b6f3", "lessThan": "774a434f8c9c8602a976b2536f65d0172a07f4d2", "status": "affected", "versionType": "git" }, { "version": "5e35941d990123f155b02d5663e51a24f816b6f3", "lessThan": "6bce72daeccca9aa1746e92d6c3d4784e71f2ebb", "status": "affected", "versionType": "git" }, { "version": "5e35941d990123f155b02d5663e51a24f816b6f3", "lessThan": "fb6c3596823ec5dd09c2123340330d7448f51a59", "status": "affected", "versionType": "git" }, { "version": "5e35941d990123f155b02d5663e51a24f816b6f3", "lessThan": "1e3a3593162c96e8a8de48b1e14f60c3b57fca8a", "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/netfilter/nf_conntrack_h323_asn1.c" ], "versions": [ { "version": "2.6.17", "status": "affected" }, { "version": "0", "lessThan": "2.6.17", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.253", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.203", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.167", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.130", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.78", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.20", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.10", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0", "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": "2.6.17", "versionEndExcluding": "5.10.253" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.17", "versionEndExcluding": "5.15.203" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.17", "versionEndExcluding": "6.1.167" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.17", "versionEndExcluding": "6.6.130" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.17", "versionEndExcluding": "6.12.78" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.17", "versionEndExcluding": "6.18.20" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.17", "versionEndExcluding": "6.19.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.17", "versionEndExcluding": "7.0" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/a2cd54b9348e485d338b3c132338a4410c99afaf" }, { "url": "https://git.kernel.org/stable/c/c95dc674ebf01ecfb40388b6facfc89b81fed3b7" }, { "url": "https://git.kernel.org/stable/c/41b417ff73a24b2c68134992cc44c88db27f482d" }, { "url": "https://git.kernel.org/stable/c/52235bf88159a1ef16434ab49e47e99c8a09ab20" }, { "url": "https://git.kernel.org/stable/c/774a434f8c9c8602a976b2536f65d0172a07f4d2" }, { "url": "https://git.kernel.org/stable/c/6bce72daeccca9aa1746e92d6c3d4784e71f2ebb" }, { "url": "https://git.kernel.org/stable/c/fb6c3596823ec5dd09c2123340330d7448f51a59" }, { "url": "https://git.kernel.org/stable/c/1e3a3593162c96e8a8de48b1e14f60c3b57fca8a" } ], "title": "netfilter: nf_conntrack_h323: fix OOB read in decode_int() CONS case", "x_generator": { "engine": "bippy-1.2.0" } }, 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