{"id":"CVE-2025-38000","title":"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() ope…","summary":"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() ope…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-416"],"vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 4.8, < 5.4.294","linux_kernel >= 5.5, < 5.10.238","linux_kernel >= 5.11, < 5.15.185","linux_kernel >= 5.16, < 6.1.141","linux_kernel >= 6.2, < 6.6.93","linux_kernel >= 6.7, < 6.12.31","linux_kernel >= 6.13, < 6.14.9","linux_kernel = 6.15","debian_linux = 11.0"],"patched":["linux_kernel 6.14.9"],"published":"2025-06-06","updated":"2026-10-15","sourceUpdated":"2026-10-15T22:18:23.970","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-38000","references":[{"url":"https://git.kernel.org/stable/c/1034e3310752e8675e313f7271b348914008719a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3f3a22eebbc32b4fa8ce9c1d5f9db214b45b9335","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3f981138109f63232a5fb7165938d4c945cc1b9d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/49b21795b8e5654a7df3d910a12e1060da4c04cf","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/89c301e929a0db14ebd94b4d97764ce1d6981653","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/93c276942e75de0e5bc91576300d292e968f5a02","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f1dde3eb17dc1b8bd07aed00004b1e05fc87a3d4","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f9f593e34d2fb67644372c8f7b033bdc622ad228","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html","label":"af854a3a-2127-422b-91ae-364da2661108"}],"tags":["nvd","cve.org"],"epss":0.00231,"epssPercentile":0.13905,"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-15T21:46:43.597631Z"},"ingestedAt":"2026-10-15T22:48:25.488Z","slug":"CVE-2025-38000","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `linux_kernel >= 4.8, < 5.4.294`\n- `linux_kernel >= 5.5, < 5.10.238`\n- `linux_kernel >= 5.11, < 5.15.185`\n- `linux_kernel >= 5.16, < 6.1.141`\n- `linux_kernel >= 6.2, < 6.6.93`\n- `linux_kernel >= 6.7, < 6.12.31`\n- `linux_kernel >= 6.13, < 6.14.9`\n- `linux_kernel = 6.15`\n- `debian_linux = 11.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 6.14.9`","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}