{ "dataType": "CVE_RECORD", "cveMetadata": { "cveId": "CVE-2024-26851", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-02-19T14:20:24.183Z", "datePublished": "2024-04-17T10:17:15.298Z", "dateUpdated": "2026-08-05T11:27:47.072Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:27:47.072Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack_h323: Add protection for bmp length out of range\n\nUBSAN load reports an exception of BRK#5515 SHIFT_ISSUE:Bitwise shifts\nthat are out of bounds for their data type.\n\nvmlinux get_bitmap(b=75) + 712\n\nvmlinux decode_seq(bs=0xFFFFFFD008037000, f=0xFFFFFFD008037018, level=134443100) + 1956\n\nvmlinux decode_choice(base=0xFFFFFFD0080370F0, level=23843636) + 1216\n\nvmlinux decode_seq(f=0xFFFFFFD0080371A8, level=134443500) + 812\n\nvmlinux decode_choice(base=0xFFFFFFD008037280, level=0) + 1216\n\nvmlinux DecodeRasMessage() + 304\n\nvmlinux ras_help() + 684\n\nvmlinux nf_confirm() + 188\n\n\nDue to abnormal data in skb->data, the extension bitmap length\nexceeds 32 when decoding ras message then uses the length to make\na shift operation. It will change into negative after several loop.\nUBSAN load could detect a negative shift as an undefined behaviour\nand reports exception.\nSo we add the protection to avoid the length exceeding 32. Or else\nit will return out of range error and stop decoding." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - The vulnerable decoder is driven entirely by attacker-supplied packet payload — a UDP datagram to port 1719 (RAS) or TCP 1720 (Q.931) processed by the in-kernel H.323 conntrack helper on any Linux router, firewall, or CPE with the ALG active. The attacker can be anywhere on the internet.\nAC:L - The 7-bit extension-bitmap length field is read verbatim from the packet, so the attacker simply sets it above 32 to force the out-of-range shift — deterministic, single packet, no timing or memory-layout dependency.\nPR:N - The helper runs on the very first packet of the flow (the trace shows it invoked from nf_confirm()), before any application-level state, credentials, or connection setup exist. A completely unauthenticated remote host triggers it.\nUI:N - Packet processing happens in softirq context on the conntrack hook with no involvement from any local user or administrator.\nS:U - The undefined behavior and its consequences are confined to the kernel of the host running the conntrack helper; no VM, IOMMU, or sandbox boundary is crossed.\nC:N - The out-of-range shift produces a garbage value in a local bitmap variable; the byte reads are still covered by nf_h323_error_boundary() and nothing is returned to the attacker, so there is no read primitive or information disclosure.\nI:N - There is no out-of-bounds write and no corruption of adjacent state — the extension loop remains bounded by f->ub, so the effect is a misparse of the attacker's own message rather than modification of kernel data.\nA:H - On kernels built with the UBSAN shift sanitizer in trap mode (widely deployed on Android/vendor kernels, and the exact configuration in the bug report) the out-of-range shift raises a BRK exception and panics the kernel, so one unauthenticated remote packet takes the box down." } ] } ], "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": "98db42191329c679f4ca52bec0b319689e1ad8cb", "status": "affected", "versionType": "git" }, { "version": "5e35941d990123f155b02d5663e51a24f816b6f3", "lessThan": "4bafcc43baf7bcf93566394dbd15726b5b456b7a", "status": "affected", "versionType": "git" }, { "version": "5e35941d990123f155b02d5663e51a24f816b6f3", "lessThan": "ccd1108b16ab572d9bf635586b0925635dbd6bbc", "status": "affected", "versionType": "git" }, { "version": "5e35941d990123f155b02d5663e51a24f816b6f3", "lessThan": "b3c0f553820516ad4b62a9390ecd28d6f73a7b13", "status": "affected", "versionType": "git" }, { "version": "5e35941d990123f155b02d5663e51a24f816b6f3", "lessThan": "39001e3c42000e7c2038717af0d33c32319ad591", "status": "affected", "versionType": "git" }, { "version": "5e35941d990123f155b02d5663e51a24f816b6f3", "lessThan": "014a807f1cc9c9d5173c1cd935835553b00d211c", "status": "affected", "versionType": "git" }, { "version": "5e35941d990123f155b02d5663e51a24f816b6f3", "lessThan": "80ee5054435a11c87c9a4f30f1ff750080c96416", "status": "affected", "versionType": "git" }, { "version": "5e35941d990123f155b02d5663e51a24f816b6f3", "lessThan": "767146637efc528b5e3d31297df115e85a2fd362", "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": "4.19.310", "lessThanOrEqual": "4.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.272", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.213", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.152", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.82", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.22", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.7.10", "lessThanOrEqual": "6.7.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.8", "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": "4.19.310" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.17", "versionEndExcluding": "5.4.272" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.17", "versionEndExcluding": "5.10.213" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.17", "versionEndExcluding": "5.15.152" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.17", "versionEndExcluding": "6.1.82" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.17", "versionEndExcluding": "6.6.22" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.17", "versionEndExcluding": "6.7.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.17", "versionEndExcluding": "6.8" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/98db42191329c679f4ca52bec0b319689e1ad8cb" }, { "url": "https://git.kernel.org/stable/c/4bafcc43baf7bcf93566394dbd15726b5b456b7a" }, { "url": "https://git.kernel.org/stable/c/ccd1108b16ab572d9bf635586b0925635dbd6bbc" }, { "url": "https://git.kernel.org/stable/c/b3c0f553820516ad4b62a9390ecd28d6f73a7b13" }, { "url": "https://git.kernel.org/stable/c/39001e3c42000e7c2038717af0d33c32319ad591" }, { "url": "https://git.kernel.org/stable/c/014a807f1cc9c9d5173c1cd935835553b00d211c" }, { "url": "https://git.kernel.org/stable/c/80ee5054435a11c87c9a4f30f1ff750080c96416" }, { "url": "https://git.kernel.org/stable/c/767146637efc528b5e3d31297df115e85a2fd362" } ], "title": "netfilter: nf_conntrack_h323: Add protection for bmp length out of range", "x_generator": { "engine": "bippy-1.2.0" } 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"affected": [ { "vendor": "Siemens", "product": "SIMATIC S7-1500 TM MFP - GNU/Linux subsystem", "versions": [ { "status": "affected", "version": "0", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" } ], "references": [ { "url": "https://cert-portal.siemens.com/productcert/html/ssa-265688.html" } ] } ] }, "dataVersion": "5.2" }