{"id":"CVE-2026-43186","revision":"1c203980e6cd4a70b24ddf8809a2b648","records":[{"revision":"1c203980e6cd4a70b24ddf8809a2b648","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-43186","aliases":[],"title":"ipv6: ioam: fix heap buffer overflow in __ioam6_fill_trace_data()","description":"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).","state":0,"publishedAt":"2026-05-06T11:27:57.053+00:00","modifiedAt":"2026-10-19T19:16:23.065+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"include/net/ioam6.h\",\n                        \"net/ipv6/exthdrs.c\",\n                        \"net/ipv6/ioam6.c\",\n                        \"net/ipv6/ioam6_iptunnel.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"9ee11f0fff205b4b3df9750bff5e94f97c71b6a0\",\n                            \"lessThan\": \"f4d9d4b8fd839719d564651671e24c62c545c23b\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9ee11f0fff205b4b3df9750bff5e94f97c71b6a0\",\n                            \"lessThan\": \"fb3c662fafebc5b9d74417ed1de8759f6bb72143\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9ee11f0fff205b4b3df9750bff5e94f97c71b6a0\",\n                            \"lessThan\": \"632d233cf2e64a46865ae2c064ae3c9df7c8864f\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9ee11f0fff205b4b3df9750bff5e94f97c71b6a0\",\n                            \"lessThan\": \"0591d6509c2ff13f09ea2998434aba0c0472e978\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9ee11f0fff205b4b3df9750bff5e94f97c71b6a0\",\n                            \"lessThan\": \"e90346a2f1e8917d5760a44a1f61c44e3b36d96b\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9ee11f0fff205b4b3df9750bff5e94f97c71b6a0\",\n                            \"lessThan\": \"ea3632aefc04205436868541638e26f4a74d5637\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9ee11f0fff205b4b3df9750bff5e94f97c71b6a0\",\n                            \"lessThan\": \"6db8b56eed62baacaf37486e83378a72635c04cc\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"include/net/ioam6.h\",\n                        \"net/ipv6/exthdrs.c\",\n                        \"net/ipv6/ioam6.c\",\n                        \"net/ipv6/ioam6_iptunnel.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"5.15\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"5.15\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.202\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.165\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.128\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.75\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.16\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.19.6\",\n                            \"lessThanOrEqual\": \"6.19.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.0\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8,"severity":"CRITICAL"}],"references":["https://git.kernel.org/stable/c/f4d9d4b8fd839719d564651671e24c62c545c23b","https://git.kernel.org/stable/c/fb3c662fafebc5b9d74417ed1de8759f6bb72143","https://git.kernel.org/stable/c/632d233cf2e64a46865ae2c064ae3c9df7c8864f","https://git.kernel.org/stable/c/0591d6509c2ff13f09ea2998434aba0c0472e978","https://git.kernel.org/stable/c/e90346a2f1e8917d5760a44a1f61c44e3b36d96b","https://git.kernel.org/stable/c/ea3632aefc04205436868541638e26f4a74d5637","https://git.kernel.org/stable/c/6db8b56eed62baacaf37486e83378a72635c04cc"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-43186","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-43186","identifiers":["CVE-2026-43186"]},"retained":false,"historicalAffected":[]}],"coverage":[]}