{"id":"CVE-2026-98570","revision":"accd88f6171e4fb49f211a781aabdfb5","records":[{"revision":"accd88f6171e4fb49f211a781aabdfb5","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-98570","aliases":[],"title":"net: ipv6: keep room for the mac header in dst_dev_overhead()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ipv6: keep room for the mac header in dst_dev_overhead()\n\nThe seg6, ioam6 and rpl lwtunnels size their skb_cow_head() request as\nthe length they are about to push plus dst_dev_overhead(), then push the\nnew headers and rebuild the mac header below them with\nskb_mac_header_rebuild(). That rebuild needs skb->mac_len of headroom,\nbut dst_dev_overhead() leaves LL_RESERVED_SPACE() of the egress device,\n16 bytes for plain Ethernet.\n\nWhere the mac header is longer than that, as it is on ingress through a\nVLAN device with reorder_hdr off, the rebuild runs out of room:\nskb_set_mac_header(skb, -skb->mac_len) computes a negative offset,\nstores it unchecked in the u16 skb->mac_header, and the memmove that\nfollows writes skb->mac_len bytes about 64 KB past skb->head.\nForwarding plain ping6 traffic through such a device reproduces it on\nall five seg6 encapsulation modes and on the rpl and ioam6 inline paths;\nskb->mac_header comes back as 65534 on a 704-byte head.\n\nReturn the larger of the two. The helper already returns skb->mac_len\nwhen it has no dst, so this only makes the other branch agree, and it\ncovers every caller rather than each call site in turn.","state":0,"publishedAt":"2026-10-18T15:18:36.308+00:00","modifiedAt":"2026-10-19T09:21:55.765+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/dst.h\"\n ],\n \"versions\": [\n {\n \"version\": \"dce525185bc92864e5a318040285ee070563fe34\",\n \"lessThan\": \"36c07127924f11fc5741a780abcaaf808fe9ef13\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"dce525185bc92864e5a318040285ee070563fe34\",\n \"lessThan\": \"87cd6b717e4069dca34e0866e57eaeb44d3b173e\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"8471e228448a818e4c27cab4b681b2e758e46cf5\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"c432cd18a07b623651ed15ea167bd303467004cc\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"634710a372ba65bee667c2f6e58a97658c639eab\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"c447c5a9c47bb4858ab12bf90879fe595d2b7f46\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"ab9de9c48316d2622d3bf353916b99971570e2c9\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"2fcc9f3798ef82399564d247458e69abd10e683b\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"371d8dc298b4f59e99b4564ac5d906fce0932c69\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"b26f015dfb07b6be12d005a0ed0c5c43b7bedbf3\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"c0b11dc50590e10590b39dcda79835cd32f49d00\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"4c12c3c8abd8b888945d31e7bdbb0d8b73032fc5\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"25d8e065c7972dc98fd7a4cac322d5367eaede88\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"4a855c5aec41bf84922224ab7a74e088776e3ac4\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"a9f0407414e16176fdbbbd298c9e18d6dfdf96bc\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"6.12.16\",\n \"lessThan\": \"6.13\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.13.4\",\n \"lessThan\": \"6.14\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.15.179\",\n \"lessThan\": \"5.16\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.1.130\",\n \"lessThan\": \"6.2\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.81\",\n \"lessThan\": \"6.7\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.10.235\",\n \"lessThan\": \"5.11\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\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/dst.h\"\n ],\n \"versions\": [\n {\n \"version\": \"6.14\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"6.14\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.2.9\",\n \"lessThanOrEqual\": \"7.2.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.3\",\n \"lessThanOrEqual\": \"*\",\n \"status\": \"unaffected\",\n \"versionType\": \"original_commit_for_fix\"\n }\n ]\n }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/36c07127924f11fc5741a780abcaaf808fe9ef13","https://git.kernel.org/stable/c/87cd6b717e4069dca34e0866e57eaeb44d3b173e"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98570","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-98570","identifiers":["CVE-2026-98570"]},"retained":false,"historicalAffected":[]}],"coverage":[]}