{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-37953","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-04-16T04:51:23.973Z","datePublished":"2025-05-20T16:01:47.818Z","dateUpdated":"2026-05-11T21:18:17.815Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-05-11T21:18:17.815Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nsch_htb: make htb_deactivate() idempotent\n\nAlan reported a NULL pointer dereference in htb_next_rb_node()\nafter we made htb_qlen_notify() idempotent.\n\nIt turns out in the following case it introduced some regression:\n\nhtb_dequeue_tree():\n  |-> fq_codel_dequeue()\n    |-> qdisc_tree_reduce_backlog()\n      |-> htb_qlen_notify()\n        |-> htb_deactivate()\n  |-> htb_next_rb_node()\n  |-> htb_deactivate()\n\nFor htb_next_rb_node(), after calling the 1st htb_deactivate(), the\nclprio[prio]->ptr could be already set to  NULL, which means\nhtb_next_rb_node() is vulnerable here.\n\nFor htb_deactivate(), although we checked qlen before calling it, in\ncase of qlen==0 after qdisc_tree_reduce_backlog(), we may call it again\nwhich triggers the warning inside.\n\nTo fix the issues here, we need to:\n\n1) Make htb_deactivate() idempotent, that is, simply return if we\n   already call it before.\n2) Make htb_next_rb_node() safe against ptr==NULL.\n\nMany thanks to Alan for testing and for the reproducer."}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/sch_htb.c"],"versions":[{"version":"e6b45f4de763b00dc1c55e685e2dd1aaf525d3c1","lessThan":"99ff8a20fd61315bf9ae627440a5ff07d22ee153","status":"affected","versionType":"git"},{"version":"32ae12ce6a9f6bace186ca7335220ff59b6cc3cd","lessThan":"a9945f7cf1709adc5d2d31cb6cfc85627ce299a8","status":"affected","versionType":"git"},{"version":"967955c9e57f8eebfccc298037d4aaf3d42bc1c9","lessThan":"c2d25fddd867ce20a266806634eeeb5c30cb520c","status":"affected","versionType":"git"},{"version":"73cf6af13153d62f9b76eff422eea79dbc70f15e","lessThan":"c928dd4f6bf0c25c72b11824a1e9ac9bd37296a0","status":"affected","versionType":"git"},{"version":"bbbf5e0f87078b715e7a665d662a2c0e77f044ae","lessThan":"31ff70ad39485698cf779f2078132d80b57f6c07","status":"affected","versionType":"git"},{"version":"0a188c0e197383683fd093ab1ea6ce9a5869a6ea","lessThan":"98cd7ed92753090a714f0802d4434314526fe61d","status":"affected","versionType":"git"},{"version":"a61f1b5921761fbaf166231418bc1db301e5bf59","lessThan":"c4792b9e38d2f61b07eac72f10909fa76130314b","status":"affected","versionType":"git"},{"version":"5ba8b837b522d7051ef81bacf3d95383ff8edce5","lessThan":"3769478610135e82b262640252d90f6efb05be71","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/sch_htb.c"],"versions":[{"version":"6.1.138","lessThan":"6.1.139","status":"affected","versionType":"semver"},{"version":"6.6.90","lessThan":"6.6.91","status":"affected","versionType":"semver"},{"version":"6.12.28","lessThan":"6.12.29","status":"affected","versionType":"semver"},{"version":"6.14.6","lessThan":"6.14.7","status":"affected","versionType":"semver"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1.138","versionEndExcluding":"6.1.139"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.90","versionEndExcluding":"6.6.91"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12.28","versionEndExcluding":"6.12.29"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.14.6","versionEndExcluding":"6.14.7"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/99ff8a20fd61315bf9ae627440a5ff07d22ee153"},{"url":"https://git.kernel.org/stable/c/a9945f7cf1709adc5d2d31cb6cfc85627ce299a8"},{"url":"https://git.kernel.org/stable/c/c2d25fddd867ce20a266806634eeeb5c30cb520c"},{"url":"https://git.kernel.org/stable/c/c928dd4f6bf0c25c72b11824a1e9ac9bd37296a0"},{"url":"https://git.kernel.org/stable/c/31ff70ad39485698cf779f2078132d80b57f6c07"},{"url":"https://git.kernel.org/stable/c/98cd7ed92753090a714f0802d4434314526fe61d"},{"url":"https://git.kernel.org/stable/c/c4792b9e38d2f61b07eac72f10909fa76130314b"},{"url":"https://git.kernel.org/stable/c/3769478610135e82b262640252d90f6efb05be71"}],"title":"sch_htb: make htb_deactivate() idempotent","x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CVE Program Container","references":[{"url":"https://lists.debian.org/debian-lts-announce/2025/08/msg00010.html"}],"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2025-11-03T19:57:42.885Z"}}]}}