{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-43186", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-01T14:12:55.991Z", "datePublished": "2026-05-06T11:27:57.053Z", "dateUpdated": "2026-08-05T12:26:24.342Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:26:24.342Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: ioam: fix heap buffer overflow in __ioam6_fill_trace_data()\n\nOn the receive path, __ioam6_fill_trace_data() uses trace->nodelen\nto decide how much data to write for each node. It trusts this field\nas-is from the incoming packet, with no consistency check against\ntrace->type (the 24-bit field that tells which data items are\npresent). A crafted packet can set nodelen=0 while setting type bits\n0-21, causing the function to write ~100 bytes past the allocated\nregion (into skb_shared_info), which corrupts adjacent heap memory\nand leads to a kernel panic.\n\nAdd a shared helper ioam6_trace_compute_nodelen() in ioam6.c to\nderive the expected nodelen from the type field, and use it:\n\n - in ioam6_iptunnel.c (send path, existing validation) to replace\n the open-coded computation;\n - in exthdrs.c (receive path, ipv6_hop_ioam) to drop packets whose\n nodelen is inconsistent with the type field, before any data is\n written.\n\nPer RFC 9197, bits 12-21 are each short (4-octet) fields, so they\nare included in IOAM6_MASK_SHORT_FIELDS (changed from 0xff100000 to\n0xff1ffc00)." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:N - The vulnerable code is reached while processing received IPv6 Hop-by-Hop IOAM options in the network stack. A remote packet sender can craft the IOAM trace header for an IOAM-enabled target.\nAC:L - Exploitation requires a malformed but straightforward IOAM Pre-allocated Trace option with inconsistent nodelen and type fields. There is no race or attacker-uncontrolled timing condition once IOAM is enabled on the target interface.\nPR:N - The packet processing path has no authentication or per-sender privilege check before calling the vulnerable fill routine. Although enabling IOAM and creating namespaces is administrative setup, a remote attacker against such a deployment needs no privileges.\nUI:N - No victim user action is needed. The vulnerable path runs automatically when the kernel receives and parses the crafted IPv6 packet.\nS:U - The corruption occurs inside the same kernel security authority that processes the packet. This is not a VM escape or other cross-scope boundary bypass.\nC:H - The bug is a kernel heap out-of-bounds write into adjacent skb memory, including skb_shared_info in the described case. Such memory corruption can be leveraged for kernel memory disclosure as part of exploitation.\nI:H - This is an out-of-bounds kernel heap write controlled by attacker-supplied packet fields and layout choices. Kernel heap corruption is defensibly exploitable for arbitrary modification or code execution.\nA:H - The fix commit states the corruption leads to a kernel panic, and malformed packets can be sent repeatedly. Kernel panic or crash is high availability impact." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/net/ioam6.h", "net/ipv6/exthdrs.c", "net/ipv6/ioam6.c", "net/ipv6/ioam6_iptunnel.c" ], "versions": [ { "version": "9ee11f0fff205b4b3df9750bff5e94f97c71b6a0", "lessThan": "f4d9d4b8fd839719d564651671e24c62c545c23b", "status": "affected", "versionType": "git" }, { "version": "9ee11f0fff205b4b3df9750bff5e94f97c71b6a0", "lessThan": "fb3c662fafebc5b9d74417ed1de8759f6bb72143", "status": "affected", "versionType": "git" }, { "version": "9ee11f0fff205b4b3df9750bff5e94f97c71b6a0", "lessThan": "632d233cf2e64a46865ae2c064ae3c9df7c8864f", "status": "affected", "versionType": "git" }, { "version": "9ee11f0fff205b4b3df9750bff5e94f97c71b6a0", "lessThan": "0591d6509c2ff13f09ea2998434aba0c0472e978", "status": "affected", "versionType": "git" }, { "version": "9ee11f0fff205b4b3df9750bff5e94f97c71b6a0", "lessThan": "e90346a2f1e8917d5760a44a1f61c44e3b36d96b", "status": "affected", "versionType": "git" }, { "version": "9ee11f0fff205b4b3df9750bff5e94f97c71b6a0", "lessThan": "ea3632aefc04205436868541638e26f4a74d5637", "status": "affected", "versionType": "git" }, { "version": "9ee11f0fff205b4b3df9750bff5e94f97c71b6a0", "lessThan": "6db8b56eed62baacaf37486e83378a72635c04cc", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/net/ioam6.h", "net/ipv6/exthdrs.c", "net/ipv6/ioam6.c", "net/ipv6/ioam6_iptunnel.c" ], "versions": [ { "version": "5.15", "status": "affected" }, { "version": "0", "lessThan": "5.15", "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": "5.15", "versionEndExcluding": "5.15.202" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.1.165" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.6.128" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.12.75" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.18.16" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.19.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "7.0" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/f4d9d4b8fd839719d564651671e24c62c545c23b" }, { "url": "https://git.kernel.org/stable/c/fb3c662fafebc5b9d74417ed1de8759f6bb72143" }, { "url": "https://git.kernel.org/stable/c/632d233cf2e64a46865ae2c064ae3c9df7c8864f" }, { "url": "https://git.kernel.org/stable/c/0591d6509c2ff13f09ea2998434aba0c0472e978" }, { "url": "https://git.kernel.org/stable/c/e90346a2f1e8917d5760a44a1f61c44e3b36d96b" }, { "url": "https://git.kernel.org/stable/c/ea3632aefc04205436868541638e26f4a74d5637" }, { "url": "https://git.kernel.org/stable/c/6db8b56eed62baacaf37486e83378a72635c04cc" } ], "title": "ipv6: ioam: fix heap buffer overflow in __ioam6_fill_trace_data()", "x_generator": { "engine": "bippy-1.2.0" } } } }