{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-37798","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-04-16T04:51:23.941Z","datePublished":"2025-05-02T14:16:02.623Z","dateUpdated":"2026-08-05T11:57:37.129Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T11:57:37.129Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ncodel: remove sch->q.qlen check before qdisc_tree_reduce_backlog()\n\nAfter making all ->qlen_notify() callbacks idempotent, now it is safe to\nremove the check of qlen!=0 from both fq_codel_dequeue() and\ncodel_qdisc_dequeue()."}],"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 state is created and triggered through tc/rtnetlink qdisc configuration (RTM_NEWQDISC/RTM_NEWTCLASS/RTM_DELTCLASS) plus locally generated traffic over a loopback or veth device. There is no remote entry point into the qdisc class hierarchy setup.\nAC:L - The attacker controls every input: the qdisc hierarchy, CoDel's target/interval (unvalidated in codel_change()), the device MTU that defeats the backlog>mtu drop guard, the traffic that fills and empties the queue, and the moment the class is deleted. The inconsistent active-but-empty class state persists indefinitely, so no race window must be won.\nPR:L - Configuring qdiscs requires CAP_NET_ADMIN, but rtnetlink checks it via sk_ns_capable(sk, net->user_ns, CAP_NET_ADMIN), which any unprivileged local user obtains inside a `unshare -Urn` user+network namespace. Per kernel scoring guidance, tc/qdisc reachable through user namespaces is Low, not High.\nUI:N - The attacker performs every step — qdisc setup, traffic generation, and class deletion — within their own namespace. No victim action or interaction is needed.\nS:U - The corruption is confined to kernel heap objects and scheduler data structures managed by the same kernel security authority. No VM, IOMMU, or sandbox boundary is crossed.\nC:H - The freed drr_class/qfq_class/hfsc_class remains linked in the parent's active list and rbtrees; after heap reclaim the attacker controls the object contents and the traversals read kernel pointers back out of it, yielding an arbitrary-read primitive and kernel address disclosure. Per guidance, use-after-free is High.\nI:H - Subsequent list_del/list_add and rb_erase operations write through pointers stored in the freed object, and drr_dequeue()/agg_dequeue() perform an indirect call via cl->qdisc->ops->peek() on reclaimed memory, giving a write primitive and control-flow hijack suitable for full privilege escalation.\nA:H - Even without successful exploitation, the dangling class in the active list/rbtree causes list and red-black-tree corruption and dereference of poisoned or freed pointers, producing a kernel oops or panic that can be triggered repeatedly by an unprivileged user."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/sch_codel.c","net/sched/sch_fq_codel.c"],"versions":[{"version":"76e3cc126bb223013a6b9a0e2a51238d1ef2e409","lessThan":"7a742a9506849d1c1aa71e36c89855ceddc7d58e","status":"affected","versionType":"git"},{"version":"76e3cc126bb223013a6b9a0e2a51238d1ef2e409","lessThan":"cc71a757da78dd4aa1b4a9b19cb011833730ccf2","status":"affected","versionType":"git"},{"version":"76e3cc126bb223013a6b9a0e2a51238d1ef2e409","lessThan":"eda741fe155ddf5ecd2dd3bfbd4fc3c0c7dbb450","status":"affected","versionType":"git"},{"version":"76e3cc126bb223013a6b9a0e2a51238d1ef2e409","lessThan":"829c49b6b2ff45b043739168fd1245e4e1a91a30","status":"affected","versionType":"git"},{"version":"76e3cc126bb223013a6b9a0e2a51238d1ef2e409","lessThan":"2f9761a94bae33d26e6a81b31b36e7d776d93dc1","status":"affected","versionType":"git"},{"version":"76e3cc126bb223013a6b9a0e2a51238d1ef2e409","lessThan":"4d55144b12e742404bb3f8fee6038bafbf45619d","status":"affected","versionType":"git"},{"version":"76e3cc126bb223013a6b9a0e2a51238d1ef2e409","lessThan":"e73c838c80dccb9e4f19becc11d9f3cb4a27d483","status":"affected","versionType":"git"},{"version":"76e3cc126bb223013a6b9a0e2a51238d1ef2e409","lessThan":"a57fe60ef4cf96bfbb6b58397ec28bdb5a5c6b31","status":"affected","versionType":"git"},{"version":"76e3cc126bb223013a6b9a0e2a51238d1ef2e409","lessThan":"342debc12183b51773b3345ba267e9263bdfaaef","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_codel.c","net/sched/sch_fq_codel.c"],"versions":[{"version":"3.5","status":"affected"},{"version":"0","lessThan":"3.5","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":"6.1.135","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.88","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.24","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.13.12","lessThanOrEqual":"6.13.*","status":"unaffected","versionType":"semver"},{"version":"6.14.3","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":"3.5","versionEndExcluding":"5.4.297"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"5.10.241"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"5.15.190"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"6.1.135"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"6.6.88"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"6.12.24"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"6.13.12"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"6.14.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"6.15"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/7a742a9506849d1c1aa71e36c89855ceddc7d58e"},{"url":"https://git.kernel.org/stable/c/cc71a757da78dd4aa1b4a9b19cb011833730ccf2"},{"url":"https://git.kernel.org/stable/c/eda741fe155ddf5ecd2dd3bfbd4fc3c0c7dbb450"},{"url":"https://git.kernel.org/stable/c/829c49b6b2ff45b043739168fd1245e4e1a91a30"},{"url":"https://git.kernel.org/stable/c/2f9761a94bae33d26e6a81b31b36e7d776d93dc1"},{"url":"https://git.kernel.org/stable/c/4d55144b12e742404bb3f8fee6038bafbf45619d"},{"url":"https://git.kernel.org/stable/c/e73c838c80dccb9e4f19becc11d9f3cb4a27d483"},{"url":"https://git.kernel.org/stable/c/a57fe60ef4cf96bfbb6b58397ec28bdb5a5c6b31"},{"url":"https://git.kernel.org/stable/c/342debc12183b51773b3345ba267e9263bdfaaef"}],"title":"codel: remove sch->q.qlen check before qdisc_tree_reduce_backlog()","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/2025/05/msg00045.html"}],"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2025-11-03T19:55:29.865Z"}}]}}