{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-38177","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-04-16T04:51:23.992Z","datePublished":"2025-07-04T12:47:09.127Z","dateUpdated":"2026-08-05T12:00:08.513Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:00:08.513Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nsch_hfsc: make hfsc_qlen_notify() idempotent\n\nhfsc_qlen_notify() is not idempotent either and not friendly\nto its callers, like fq_codel_dequeue(). Let's make it idempotent\nto ease qdisc_tree_reduce_backlog() callers' life:\n\n1. update_vf() decreases cl->cl_nactive, so we can check whether it is\nnon-zero before calling it.\n\n2. eltree_remove() always removes RB node cl->el_node, but we can use\n   RB_EMPTY_NODE() + RB_CLEAR_NODE() to make it safe."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The vulnerable path is reached by configuring HFSC classes and child qdiscs via rtnetlink (`tc`) and driving local packet flow through them, which requires local system access. Remote packets alone cannot establish the required qdisc hierarchy.\nAC:L - The attacker fully controls every precondition — the qdisc/class topology, the child qdisc that re-enters `qdisc_tree_reduce_backlog()`, the packet, and the class deletion — and the sibling commit ships a deterministic shell reproducer. This is a reentrancy/accounting bug, not a race the attacker must win.\nPR:L - `tc` qdisc/class operations are gated by `netlink_net_capable(skb, CAP_NET_ADMIN)`, which resolves to `netlink_ns_capable(skb, sock_net(sk)->user_ns, ...)` — namespace-relative, so an unprivileged user obtains it with `unshare -Urn` and can build the full hierarchy on `lo` inside that netns.\nUI:N - The attacker performs the qdisc setup, packet transmission, and class deletion entirely on their own; no victim action or cooperation is needed.\nS:U - The corruption is confined to kernel memory within the same security authority; there is no VM, IOMMU, or sandbox boundary crossed.\nC:H - Dangling `hfsc_class` rb_nodes left in `q->eligible`/`vt_tree` are dereferenced by `eltree_get_mindl()`/`vttree_get_minvt()` after `kfree()`, giving a use-after-free read over reclaimed heap contents the attacker can spray, enabling arbitrary kernel memory disclosure.\nI:H - Double `rb_erase()` on a stale node writes through an attacker-influenceable parent pointer, and subsequent `eltree_update()`/`rb_insert` operate on freed memory — yielding a write primitive; the same HFSC rbtree-corruption primitive has a public working local privilege escalation (CVE-2025-38001, \"rbtree family drama\").\nA:H - Red-black tree corruption and use-after-free on freed `hfsc_class` objects reliably produce oopses, KASAN splats, and kernel panics, taking the system down."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/sch_hfsc.c"],"versions":[{"version":"959466588aa7f84ccf79ae36a1d89542eaf9aaec","lessThan":"9a5fd5c2f4d4afdd5e405083ee53e0789ce76956","status":"affected","versionType":"git"},{"version":"959466588aa7f84ccf79ae36a1d89542eaf9aaec","lessThan":"72c61ffbeeb8c50f6d4d70c65d3283aa1bac57a7","status":"affected","versionType":"git"},{"version":"959466588aa7f84ccf79ae36a1d89542eaf9aaec","lessThan":"a5efc95a33bd4fcb879250852828cc58c7862970","status":"affected","versionType":"git"},{"version":"959466588aa7f84ccf79ae36a1d89542eaf9aaec","lessThan":"0475c85426b18eccdcb7f9fb58d8f8e9c6c58c87","status":"affected","versionType":"git"},{"version":"959466588aa7f84ccf79ae36a1d89542eaf9aaec","lessThan":"9030a91235ae4845ec71902c3e0cecfc9ed1f2df","status":"affected","versionType":"git"},{"version":"959466588aa7f84ccf79ae36a1d89542eaf9aaec","lessThan":"d06476714d2819b550e0cc39222347e2c8941c9d","status":"affected","versionType":"git"},{"version":"959466588aa7f84ccf79ae36a1d89542eaf9aaec","lessThan":"c1175c4ad01dbc9c979d099861fa90a754f72059","status":"affected","versionType":"git"},{"version":"959466588aa7f84ccf79ae36a1d89542eaf9aaec","lessThan":"51eb3b65544c9efd6a1026889ee5fb5aa62da3bb","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/sch_hfsc.c"],"versions":[{"version":"4.14","status":"affected"},{"version":"0","lessThan":"4.14","status":"unaffected","versionType":"semver"},{"version":"5.4.297","lessThanOrEqual":"5.4.*","status":"unaffected","versionType":"semver"},{"version":"5.10.241","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.190","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.138","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.90","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.28","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.14.6","lessThanOrEqual":"6.14.*","status":"unaffected","versionType":"semver"},{"version":"6.15","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.14","versionEndExcluding":"5.4.297"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.14","versionEndExcluding":"5.10.241"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.14","versionEndExcluding":"5.15.190"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.14","versionEndExcluding":"6.1.138"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.14","versionEndExcluding":"6.6.90"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.14","versionEndExcluding":"6.12.28"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.14","versionEndExcluding":"6.14.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.14","versionEndExcluding":"6.15"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/9a5fd5c2f4d4afdd5e405083ee53e0789ce76956"},{"url":"https://git.kernel.org/stable/c/72c61ffbeeb8c50f6d4d70c65d3283aa1bac57a7"},{"url":"https://git.kernel.org/stable/c/a5efc95a33bd4fcb879250852828cc58c7862970"},{"url":"https://git.kernel.org/stable/c/0475c85426b18eccdcb7f9fb58d8f8e9c6c58c87"},{"url":"https://git.kernel.org/stable/c/9030a91235ae4845ec71902c3e0cecfc9ed1f2df"},{"url":"https://git.kernel.org/stable/c/d06476714d2819b550e0cc39222347e2c8941c9d"},{"url":"https://git.kernel.org/stable/c/c1175c4ad01dbc9c979d099861fa90a754f72059"},{"url":"https://git.kernel.org/stable/c/51eb3b65544c9efd6a1026889ee5fb5aa62da3bb"}],"title":"sch_hfsc: make hfsc_qlen_notify() idempotent","x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CVE Program Container","references":[{"url":"https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html"},{"url":"https://lists.debian.org/debian-lts-announce/2025/08/msg00010.html"}],"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2025-11-03T19:58:30.487Z"}},{"metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2025-38177","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-06-10T20:40:35.261574Z"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-06-11T18:44:03.284Z"}}]}}