{"id":"CVE-2025-21703","revision":null,"records":[{"revision":"0fc2d22c023f4fc5a7b522654a714625","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2025-21703","aliases":[],"title":"netem: Update sch->q.qlen before qdisc_tree_reduce_backlog()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetem: Update sch->q.qlen before qdisc_tree_reduce_backlog()\n\nqdisc_tree_reduce_backlog() notifies parent qdisc only if child\nqdisc becomes empty, therefore we need to reduce the backlog of the\nchild qdisc before calling it. Otherwise it would miss the opportunity\nto call cops->qlen_notify(), in the case of DRR, it resulted in UAF\nsince DRR uses ->qlen_notify() to maintain its active list.","state":0,"publishedAt":"2025-02-18T14:37:44.261+00:00","modifiedAt":"2026-10-15T01:03:25.306+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/sched/sch_netem.c\"\n ],\n \"versions\": [\n {\n \"version\": \"83c6ab12f08dcc09d4c5ac86fdb89736b28f1d31\",\n \"lessThan\": \"e395fec75ac2dbffc99b4bce57b7f1f3c5449f2c\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"216509dda290f6db92c816dd54b83c1df9da9e76\",\n \"lessThan\": \"7f31d74fcc556a9166b1bb20515542de7bb939d1\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"c2047b0e216c8edce227d7c42f99ac2877dad0e4\",\n \"lessThan\": \"98a2c685293aae122f688cde11d9334dddc5d207\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"10df49cfca73dfbbdb6c4150d859f7e8926ae427\",\n \"lessThan\": \"7b79ca9a1de6a428d486ff52fb3d602321c08f55\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"3824c5fad18eeb7abe0c4fc966f29959552dca3e\",\n \"lessThan\": \"1f8e3f4a4b8b90ad274dfbc66fc7d55cb582f4d5\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"356078a5c55ec8d2061fcc009fb8599f5b0527f9\",\n \"lessThan\": \"6312555249082d6d8cc5321ff725df05482d8b83\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"f8d4bc455047cf3903cd6f85f49978987dbb3027\",\n \"lessThan\": \"839ecc583fa00fab785fde1c85a326743657fd32\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"f8d4bc455047cf3903cd6f85f49978987dbb3027\",\n \"lessThan\": \"638ba5089324796c2ee49af10427459c2de35f71\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"5.4.288\",\n \"lessThan\": \"5.4.291\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.10.232\",\n \"lessThan\": \"5.10.235\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.15.175\",\n \"lessThan\": \"5.15.179\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.1.121\",\n \"lessThan\": \"6.1.129\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.67\",\n \"lessThan\": \"6.6.78\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.6\",\n \"lessThan\": \"6.12.14\",\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 \"net/sched/sch_netem.c\"\n ],\n \"versions\": [\n {\n \"version\": \"6.13\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"6.13\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.4.291\",\n \"lessThanOrEqual\": \"5.4.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.10.235\",\n \"lessThanOrEqual\": \"5.10.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.15.179\",\n \"lessThanOrEqual\": \"5.15.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.1.129\",\n \"lessThanOrEqual\": \"6.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.78\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.14\",\n \"lessThanOrEqual\": \"6.12.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.13.3\",\n \"lessThanOrEqual\": \"6.13.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.14\",\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/e395fec75ac2dbffc99b4bce57b7f1f3c5449f2c","https://git.kernel.org/stable/c/7f31d74fcc556a9166b1bb20515542de7bb939d1","https://git.kernel.org/stable/c/98a2c685293aae122f688cde11d9334dddc5d207","https://git.kernel.org/stable/c/7b79ca9a1de6a428d486ff52fb3d602321c08f55","https://git.kernel.org/stable/c/1f8e3f4a4b8b90ad274dfbc66fc7d55cb582f4d5","https://git.kernel.org/stable/c/6312555249082d6d8cc5321ff725df05482d8b83","https://git.kernel.org/stable/c/839ecc583fa00fab785fde1c85a326743657fd32","https://git.kernel.org/stable/c/638ba5089324796c2ee49af10427459c2de35f71"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-21703","license":"CVE Program Terms of Use","key":"cve-program:CVE-2025-21703","identifiers":["CVE-2025-21703"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all 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