{"cve":"CVE-2025-38000","nvd":{"published":"2025-06-06T13:15:39.870","modified":"2026-10-15T22:18:23.970","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsch_hfsc: Fix qlen accounting bug when using peek in hfsc_enqueue()\n\nWhen enqueuing the first packet to an HFSC class, hfsc_enqueue() calls the\nchild qdisc's peek() operation before incrementing sch->q.qlen and\nsch->qstats.backlog. If the child qdisc uses qdisc_peek_dequeued(), this may\ntrigger an immediate dequeue and potential packet drop. In such cases,\nqdisc_tree_reduce_backlog() is called, but the HFSC qdisc's qlen and backlog\nhave not yet been updated, leading to inconsistent queue accounting. This\ncan leave an empty HFSC class in the active list, causing further\nconsequences like use-after-free.\n\nThis patch fixes the bug by moving the increment of sch->q.qlen and\nsch->qstats.backlog before the call to the child qdisc's peek() operation.\nThis ensures that queue length and backlog are always accurate when packet\ndrops or dequeues are triggered during the peek.","cvss_v4":null,"cvss_v3":{"version":"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},"cwes":["CWE-416"],"references":["https://git.kernel.org/stable/c/1034e3310752e8675e313f7271b348914008719a","https://git.kernel.org/stable/c/3f3a22eebbc32b4fa8ce9c1d5f9db214b45b9335","https://git.kernel.org/stable/c/3f981138109f63232a5fb7165938d4c945cc1b9d","https://git.kernel.org/stable/c/49b21795b8e5654a7df3d910a12e1060da4c04cf","https://git.kernel.org/stable/c/89c301e929a0db14ebd94b4d97764ce1d6981653"],"products":["debian:debian_linux","linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:02:23.998251710+00:00"},"epss":{"cve":"CVE-2025-38000","score":0.00231,"percentile":0.13844,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}