{"id":"CVE-2026-90054","revision":"6bf21dc04d77421ab385590258b83cbc","records":[{"revision":"6bf21dc04d77421ab385590258b83cbc","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-90054","aliases":[],"title":"tcp: fix corruption of urgent data on multi-segment retransmit","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: fix corruption of urgent data on multi-segment retransmit\n\nOn the normal xmit path, while in urgent mode we refuse to build a\nmulti-segment TSO packet, so every segment gets its own urg_ptr:\n\n\t/* tcp_write_xmit() */\n\tlimit = mss_now;\n\tif (tso_segs > 1 && !tcp_urg_mode(tp))\n\t\tlimit = tcp_mss_split_point(...);\n\nThe retransmit path has no such guard. __tcp_retransmit_skb() builds a\nsegs > 1 skb and hands it to the GSO layer, which only advances th->seq\nper segment and copies urg_ptr verbatim:\n\n\t/* __tcp_retransmit_skb() */\n\tlen = cur_mss * segs;\t\t/* segs > 1, no urg_mode check */\n\t...\n\t/* tcp_gso_segment(): bumps seq only, urg_ptr is copied */\n\nurg_ptr is an offset from the segment's own seq, so a copied value points\nat a different place on each segment. The receiver rebuilds the absolute\nurgent seq as seg.seq + urg_ptr, so it walks a moving urgent point instead\nof the one OOB byte:\n\n\tseg1 seq 1 urg_ptr 5001 -> urgent @ 5001 (ok)\n\tseg2 seq 1001 urg_ptr 5001 -> urgent @ 6001 (wrong, +MSS)\n\tseg3 seq 2001 urg_ptr 5001 -> urgent @ 7001 (wrong, +2*MSS)\n\nThe real OOB byte is never pointed at, so the receiver stops splicing it\nout and delivers it as normal in-band data, corrupting the stream.\n\nGuard the retransmit length like the xmit path: keep segs = 1 while in\nurgent mode.","state":0,"publishedAt":"2026-09-17T16:05:39.632+00:00","modifiedAt":"2026-10-19T08:57:11.615+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/ipv4/tcp_output.c\"\n ],\n \"versions\": [\n {\n \"version\": \"10d3be569243def8d92ac3722395ef5a59c504e6\",\n \"lessThan\": \"8eb51013b6308870479a64b4a2a018697b997849\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"10d3be569243def8d92ac3722395ef5a59c504e6\",\n \"lessThan\": \"711bfd762bec05fb19bc3b17cbb157c39f4e66da\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"10d3be569243def8d92ac3722395ef5a59c504e6\",\n \"lessThan\": \"3d4e005c198dc410ad568f832bffa7569c059ff8\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"10d3be569243def8d92ac3722395ef5a59c504e6\",\n \"lessThan\": \"4fd2ee4ac154c204d95d8db72221446dac5af9b8\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"10d3be569243def8d92ac3722395ef5a59c504e6\",\n \"lessThan\": \"ebe55406404f3cb28e36d2b668e2c6c05026ec29\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"10d3be569243def8d92ac3722395ef5a59c504e6\",\n \"lessThan\": \"b8f08a94b2a4addc39249dcf9c792e786108621b\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"10d3be569243def8d92ac3722395ef5a59c504e6\",\n \"lessThan\": \"47eb90299e6882d6445672530dd7c51ac33ebdbd\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"10d3be569243def8d92ac3722395ef5a59c504e6\",\n \"lessThan\": \"ce2b807f42ed5e55567b8864ab72963f90779270\",\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/ipv4/tcp_output.c\"\n ],\n \"versions\": [\n {\n \"version\": \"4.7\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"4.7\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.10.270\",\n \"lessThanOrEqual\": \"5.10.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.15.221\",\n \"lessThanOrEqual\": \"5.15.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.1.188\",\n \"lessThanOrEqual\": \"6.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.157\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.110\",\n \"lessThanOrEqual\": \"6.12.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.18.52\",\n \"lessThanOrEqual\": \"6.18.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.2.6\",\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/8eb51013b6308870479a64b4a2a018697b997849","https://git.kernel.org/stable/c/711bfd762bec05fb19bc3b17cbb157c39f4e66da","https://git.kernel.org/stable/c/3d4e005c198dc410ad568f832bffa7569c059ff8","https://git.kernel.org/stable/c/4fd2ee4ac154c204d95d8db72221446dac5af9b8","https://git.kernel.org/stable/c/ebe55406404f3cb28e36d2b668e2c6c05026ec29","https://git.kernel.org/stable/c/b8f08a94b2a4addc39249dcf9c792e786108621b","https://git.kernel.org/stable/c/47eb90299e6882d6445672530dd7c51ac33ebdbd","https://git.kernel.org/stable/c/ce2b807f42ed5e55567b8864ab72963f90779270"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-90054","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-90054","identifiers":["CVE-2026-90054"]},"retained":false,"historicalAffected":[]}],"coverage":[]}