{"id":"CVE-2026-68297","revision":"a972cda622434571a79770bf20a9cd65","records":[{"revision":"a972cda622434571a79770bf20a9cd65","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-68297","aliases":[],"title":"tipc: fix u16 MTU truncation in media and bearer MTU validation","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: fix u16 MTU truncation in media and bearer MTU validation\n\nBoth TIPC_NL_MEDIA_SET and TIPC_NL_BEARER_SET accept user-supplied\nMTU values but only enforce a minimum bound, not a maximum. When a user\nsets the MTU to a value exceeding U16_MAX (65535), it passes validation\nbut is silently truncated when assigned to u16 fields l->mtu and\nl->advertised_mtu in tipc_link_create(). Values like 65536 (0x10000)\ntruncate to 0, causing a division by zero in tipc_link_set_queue_limits()\nwhich computes TIPC_MAX_PUBL / (l->mtu / ITEM_SIZE). Other overflowing\nvalues (e.g. 65537-131071) produce small incorrect MTU values, resulting\nin link malfunction behaviors.\n\nCrash stack (triggered as unprivileged user via user namespace):\n\n tipc_link_set_queue_limits net/tipc/link.c:2531\n tipc_link_create net/tipc/link.c:520\n tipc_node_check_dest net/tipc/node.c:1279\n tipc_disc_rcv net/tipc/discover.c:252\n tipc_rcv net/tipc/node.c:2129\n tipc_udp_recv net/tipc/udp_media.c:392\n\nTwo independent paths lack the upper bound check:\n1. tipc_udp_mtu_bad() -- called from __tipc_nl_media_set() (MEDIA_SET)\n2. inline check in __tipc_nl_bearer_set() at bearer.c:1160 (BEARER_SET)\n\nFix both by rejecting MTU values above U16_MAX.","state":0,"publishedAt":"2026-08-10T12:02:30.721+00:00","modifiedAt":"2026-10-19T21:09:03.754+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 \"net/tipc/netlink.c\"\n ],\n \"versions\": [\n {\n \"version\": \"901271e0403af638c224987c2a4e55cebade7e91\",\n \"lessThan\": \"8bfdfe0dbb36a650b7c4dec1aeae078319938a0b\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"901271e0403af638c224987c2a4e55cebade7e91\",\n \"lessThan\": \"dc4b577a083b361d25e118dc96d8281255ebe22c\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"901271e0403af638c224987c2a4e55cebade7e91\",\n \"lessThan\": \"dfdfd987f1917c84766e097a6120a1f3f1634940\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"901271e0403af638c224987c2a4e55cebade7e91\",\n \"lessThan\": \"f02334a9e378f7e07232b26dc3d2ab353339f040\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"901271e0403af638c224987c2a4e55cebade7e91\",\n \"lessThan\": \"f4013598b69457dbea350df52e52daea6faef8eb\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"901271e0403af638c224987c2a4e55cebade7e91\",\n \"lessThan\": \"1b8fb5a20508bfb0db854e01214888c761b3a911\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"901271e0403af638c224987c2a4e55cebade7e91\",\n \"lessThan\": \"c1cda72f6acec02ebd45d913bf8527ff77336ba6\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"901271e0403af638c224987c2a4e55cebade7e91\",\n \"lessThan\": \"9f29cd8a8e7901a2617c8064ce9f50fc67b97cb8\",\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 \"net/tipc/netlink.c\"\n ],\n \"versions\": [\n {\n \"version\": \"4.18\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"4.18\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.10.265\",\n \"lessThanOrEqual\": \"5.10.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.15.216\",\n \"lessThanOrEqual\": \"5.15.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.1.183\",\n \"lessThanOrEqual\": \"6.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.148\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.101\",\n \"lessThanOrEqual\": \"6.12.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.18.42\",\n \"lessThanOrEqual\": \"6.18.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.1.6\",\n \"lessThanOrEqual\": \"7.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.2\",\n \"lessThanOrEqual\": \"*\",\n \"status\": \"unaffected\",\n \"versionType\": \"original_commit_for_fix\"\n }\n ]\n }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/8bfdfe0dbb36a650b7c4dec1aeae078319938a0b","https://git.kernel.org/stable/c/dc4b577a083b361d25e118dc96d8281255ebe22c","https://git.kernel.org/stable/c/dfdfd987f1917c84766e097a6120a1f3f1634940","https://git.kernel.org/stable/c/f02334a9e378f7e07232b26dc3d2ab353339f040","https://git.kernel.org/stable/c/f4013598b69457dbea350df52e52daea6faef8eb","https://git.kernel.org/stable/c/1b8fb5a20508bfb0db854e01214888c761b3a911","https://git.kernel.org/stable/c/c1cda72f6acec02ebd45d913bf8527ff77336ba6","https://git.kernel.org/stable/c/9f29cd8a8e7901a2617c8064ce9f50fc67b97cb8"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-68297","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-68297","identifiers":["CVE-2026-68297"]},"retained":false,"historicalAffected":[]}],"coverage":[]}