{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-23455", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-01-13T15:37:46.020Z", "datePublished": "2026-04-03T15:15:36.869Z", "dateUpdated": "2026-08-05T12:21:54.080Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:21:54.080Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack_h323: check for zero length in DecodeQ931()\n\nIn DecodeQ931(), the UserUserIE code path reads a 16-bit length from\nthe packet, then decrements it by 1 to skip the protocol discriminator\nbyte before passing it to DecodeH323_UserInformation(). If the encoded\nlength is 0, the decrement wraps to -1, which is then passed as a\nlarge value to the decoder, leading to an out-of-bounds read.\n\nAdd a check to ensure len is positive after the decrement." } ], "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 H.323/Q.931 conntrack helper parses TCP network traffic, typically on H.323 call signaling flows through a firewall/NAT gateway. A remote peer can supply the malformed TPKT/Q.931 packet once the helper is active for that flow.\nAC:L - The trigger is a deterministic zero-length UserUserIE in an otherwise reachable Q.931 message; there is no race or condition outside the attacker's control. TCP establishment and helper deployment are normal operating conditions for the affected subsystem.\nPR:N - The attacker only needs to send network traffic to or through a system using the H.323 conntrack helper. No authentication or local privileges are required on the target system.\nUI:N - Exploitation occurs during automatic packet processing in the kernel netfilter path. No victim user action is required.\nS:U - The vulnerable component and impacted resources are within the same kernel/network filtering security authority. This is not a VM escape, IOMMU bypass, or cross-sandbox boundary violation.\nC:H - The integer underflow turns a zero encoded length into a huge decoder length, causing an out-of-bounds read beyond the packet buffer. Under the kernel guidance, an unbounded out-of-bounds read is High confidentiality impact.\nI:N - The bug is a read-side parser bounds failure and does not provide an out-of-bounds write, arbitrary write primitive, or direct control-flow corruption. Any resulting malformed conntrack processing is not enough to justify kernel data integrity compromise.\nA:H - The out-of-bounds read can fault or otherwise destabilize kernel packet processing, producing an oops/panic or repeated denial of service. A remote attacker can resend malformed packets to retrigger it." } ] } ], "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": "2121f5fbe88daff0f1fc5bc47d359426c74b86b0", "status": "affected", "versionType": "git" }, { "version": "5e35941d990123f155b02d5663e51a24f816b6f3", "lessThan": "65fa92f79677858b14b9e4b7275f26639afe2710", "status": "affected", "versionType": "git" }, { "version": "5e35941d990123f155b02d5663e51a24f816b6f3", "lessThan": "495e97af9e7249ee02b72bb1d0848a6efc3700f4", "status": "affected", "versionType": "git" }, { "version": "5e35941d990123f155b02d5663e51a24f816b6f3", "lessThan": "f5e4f4e4cdb75ec36802059a94195a31f193da60", "status": "affected", "versionType": "git" }, { "version": "5e35941d990123f155b02d5663e51a24f816b6f3", "lessThan": "633e8f87dad32263f6a57dccdb873f042c062111", "status": "affected", "versionType": "git" }, { "version": "5e35941d990123f155b02d5663e51a24f816b6f3", "lessThan": "9d00fe7d6d7c5b5f1065a6e042b54f2e44bd6df8", "status": "affected", "versionType": "git" }, { "version": "5e35941d990123f155b02d5663e51a24f816b6f3", "lessThan": "b652b05d51003ac074b912684f9ec7486231717b", "status": "affected", "versionType": "git" }, { "version": "5e35941d990123f155b02d5663e51a24f816b6f3", "lessThan": "f173d0f4c0f689173f8cdac79991043a4a89bf66", "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/2121f5fbe88daff0f1fc5bc47d359426c74b86b0" }, { "url": "https://git.kernel.org/stable/c/65fa92f79677858b14b9e4b7275f26639afe2710" }, { "url": "https://git.kernel.org/stable/c/495e97af9e7249ee02b72bb1d0848a6efc3700f4" }, { "url": "https://git.kernel.org/stable/c/f5e4f4e4cdb75ec36802059a94195a31f193da60" }, { "url": "https://git.kernel.org/stable/c/633e8f87dad32263f6a57dccdb873f042c062111" }, { "url": "https://git.kernel.org/stable/c/9d00fe7d6d7c5b5f1065a6e042b54f2e44bd6df8" }, { "url": "https://git.kernel.org/stable/c/b652b05d51003ac074b912684f9ec7486231717b" }, { "url": "https://git.kernel.org/stable/c/f173d0f4c0f689173f8cdac79991043a4a89bf66" } ], "title": "netfilter: nf_conntrack_h323: check for zero length in DecodeQ931()", "x_generator": { "engine": "bippy-1.2.0" } }, 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