{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-43233", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-01T14:12:55.995Z", "datePublished": "2026-05-06T11:28:29.565Z", "dateUpdated": "2026-08-05T12:26:46.159Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:26:46.159Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack_h323: fix OOB read in decode_choice()\n\nIn decode_choice(), the boundary check before get_len() uses the\nvariable `len`, which is still 0 from its initialization at the top of\nthe function:\n\n unsigned int type, ext, len = 0;\n ...\n if (ext || (son->attr & OPEN)) {\n BYTE_ALIGN(bs);\n if (nf_h323_error_boundary(bs, len, 0)) /* len is 0 here */\n return H323_ERROR_BOUND;\n len = get_len(bs); /* OOB read */\n\nWhen the bitstream is exactly consumed (bs->cur == bs->end), the check\nnf_h323_error_boundary(bs, 0, 0) evaluates to (bs->cur + 0 > bs->end),\nwhich is false. The subsequent get_len() call then dereferences\n*bs->cur++, reading 1 byte past the end of the buffer. If that byte\nhas bit 7 set, get_len() reads a second byte as well.\n\nThis can be triggered remotely by sending a crafted Q.931 SETUP message\nwith a User-User Information Element containing exactly 2 bytes of\nPER-encoded data ({0x08, 0x00}) to port 1720 through a firewall with\nthe nf_conntrack_h323 helper active. The decoder fully consumes the\nPER buffer before reaching this code path, resulting in a 1-2 byte\nheap-buffer-overflow read confirmed by AddressSanitizer.\n\nFix this by checking for 2 bytes (the maximum that get_len() may read)\ninstead of the uninitialized `len`. This matches the pattern used at\nevery other get_len() call site in the same file, where the caller\nchecks for 2 bytes of available data before calling get_len()." } ], "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 H.323 conntrack Q.931 helper processes TCP/1720 network traffic, and the fix explicitly documents remote triggering with a crafted Q.931 SETUP User-User IE through a firewall with the helper active.\nAC:L - The trigger is a deterministic malformed PER buffer of exact length; no race, heap grooming, or victim-controlled timing is required beyond the helper being active.\nPR:N - The attacker only sends network packets to a system/firewall where the H.323 helper is configured; the Q.931 parsing path has no authentication or attacker privilege check.\nUI:N - No victim user action is needed once the helper is active; packet receipt alone drives conntrack into the decoder.\nS:U - The impact remains within the kernel/network filtering security authority and does not cross a VM, IOMMU, or other separate security boundary.\nC:L - The bug performs a strictly bounded 1-2 byte out-of-bounds heap read via get_len(), so any confidentiality impact is limited rather than arbitrary memory disclosure.\nI:N - The vulnerable operation is read-only, and the subsequent bounds check returns an error; there is no out-of-bounds write or structure corruption.\nA:H - The remotely triggerable kernel heap out-of-bounds read is reachable repeatedly from packet processing and can cause sanitizer/oops/panic-style kernel failure on 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": "ec8a8f3c31ddef0a7d9626c4b8a4baa30f3b80aa", "lessThan": "bcb50aa0b8f2b74a9fe5a1c7bee6f2657a288041", "status": "affected", "versionType": "git" }, { "version": "ec8a8f3c31ddef0a7d9626c4b8a4baa30f3b80aa", "lessThan": "2a3aac4205e7d2f1aca2e3827de8cdd517d36c4a", "status": "affected", "versionType": "git" }, { "version": "ec8a8f3c31ddef0a7d9626c4b8a4baa30f3b80aa", "lessThan": "81f2fc5b0d0cf4696146f00f837596d10b92dead", "status": "affected", "versionType": "git" }, { "version": "ec8a8f3c31ddef0a7d9626c4b8a4baa30f3b80aa", "lessThan": "7ef82863d42261817a6394c6c881bd6757a70f16", "status": "affected", "versionType": "git" }, { "version": "ec8a8f3c31ddef0a7d9626c4b8a4baa30f3b80aa", "lessThan": "53d32735d77ab56cc3fc7bd53a7d099418f19be1", "status": "affected", "versionType": "git" }, { "version": "ec8a8f3c31ddef0a7d9626c4b8a4baa30f3b80aa", "lessThan": "f0a83d0a4b7c127d32ac06d607a9214937716129", "status": "affected", "versionType": "git" }, { "version": "ec8a8f3c31ddef0a7d9626c4b8a4baa30f3b80aa", "lessThan": "35f1943d242e1b9f0b6e91c0c93bfb293a9f8224", "status": "affected", "versionType": "git" }, { "version": "ec8a8f3c31ddef0a7d9626c4b8a4baa30f3b80aa", "lessThan": "baed0d9ba91d4f390da12d5039128ee897253d60", "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": "4.15", "status": "affected" }, { "version": "0", "lessThan": "4.15", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.252", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.202", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.165", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.128", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.75", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.16", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.6", "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": "4.15", "versionEndExcluding": "5.10.252" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "5.15.202" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "6.1.165" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "6.6.128" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "6.12.75" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "6.18.16" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "6.19.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "7.0" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/bcb50aa0b8f2b74a9fe5a1c7bee6f2657a288041" }, { "url": "https://git.kernel.org/stable/c/2a3aac4205e7d2f1aca2e3827de8cdd517d36c4a" }, { "url": "https://git.kernel.org/stable/c/81f2fc5b0d0cf4696146f00f837596d10b92dead" }, { "url": "https://git.kernel.org/stable/c/7ef82863d42261817a6394c6c881bd6757a70f16" }, { "url": "https://git.kernel.org/stable/c/53d32735d77ab56cc3fc7bd53a7d099418f19be1" }, { "url": "https://git.kernel.org/stable/c/f0a83d0a4b7c127d32ac06d607a9214937716129" }, { "url": "https://git.kernel.org/stable/c/35f1943d242e1b9f0b6e91c0c93bfb293a9f8224" }, { "url": "https://git.kernel.org/stable/c/baed0d9ba91d4f390da12d5039128ee897253d60" } ], "title": "netfilter: nf_conntrack_h323: fix OOB read in decode_choice()", "x_generator": { "engine": "bippy-1.2.0" } } } }