{"id":"CVE-2025-68325","summary":"net/sched: sch_cake: Fix incorrect qlen reduction in cake_drop","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_cake: Fix incorrect qlen reduction in cake_drop\n\nIn cake_drop(), qdisc_tree_reduce_backlog() is used to update the qlen\nand backlog of the qdisc hierarchy. Its caller, cake_enqueue(), assumes\nthat the parent qdisc will enqueue the current packet. However, this\nassumption breaks when cake_enqueue() returns NET_XMIT_CN: the parent\nqdisc stops enqueuing current packet, leaving the tree qlen/backlog\naccounting inconsistent. This mismatch can lead to a NULL dereference\n(e.g., when the parent Qdisc is qfq_qdisc).\n\nThis patch computes the qlen/backlog delta in a more robust way by\nobserving the difference before and after the series of cake_drop()\ncalls, and then compensates the qdisc tree accounting if cake_enqueue()\nreturns NET_XMIT_CN.\n\nTo ensure correct compensation when ACK thinning is enabled, a new\nvariable is introduced to keep qlen unchanged.","modified":"2026-03-31T17:29:31.411633Z","published":"2025-12-18T15:02:50.214Z","related":["SUSE-SU-2026:0447-1","SUSE-SU-2026:0472-1","SUSE-SU-2026:0587-1","SUSE-SU-2026:20477-1","SUSE-SU-2026:20498-1","SUSE-SU-2026:20555-1","SUSE-SU-2026:20599-1","SUSE-SU-2026:20615-1","SUSE-SU-2026:20845-1","SUSE-SU-2026:20876-1","openSUSE-SU-2025:15836-1","openSUSE-SU-2026:10301-1","openSUSE-SU-2026:20287-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/68xxx/CVE-2025-68325.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0b6216f9b3d1c33c76f74511026e5de5385ee520"},{"type":"WEB","url":"https://git.kernel.org/stable/c/38abf6e931b169ea88d7529b49096f53a5dcf8fe"},{"type":"WEB","url":"https://git.kernel.org/stable/c/3ed6c458530a547ed0c9ea0b02b19bab620be88b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/529c284cc2815c8350860e9a31722050fe7117cb"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9fefc78f7f02d71810776fdeb119a05a946a27cc"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a3f4e3de41a3f115db35276c6b186ccbc913934a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d01f0e072dadb02fe10f436b940dd957aff0d7d4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/fcb91be52eb6e92e00b533ebd7c77fecada537e1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/68xxx/CVE-2025-68325.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-68325"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"de04ddd2980b48caa8d7e24a7db2742917a8b280"},{"fixed":"a3f4e3de41a3f115db35276c6b186ccbc913934a"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"0dacfc5372e314d1219f03e64dde3ab495a5a25e"},{"fixed":"38abf6e931b169ea88d7529b49096f53a5dcf8fe"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"710866fc0a64eafcb8bacd91bcb1329eb7e5035f"},{"fixed":"fcb91be52eb6e92e00b533ebd7c77fecada537e1"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"aa12ee1c1bd260943fd6ab556d8635811c332eeb"},{"fixed":"d01f0e072dadb02fe10f436b940dd957aff0d7d4"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"ff57186b2cc39766672c4c0332323933e5faaa88"},{"fixed":"0b6216f9b3d1c33c76f74511026e5de5385ee520"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"15de71d06a400f7fdc15bf377a2552b0ec437cf5"},{"fixed":"529c284cc2815c8350860e9a31722050fe7117cb"},{"fixed":"3ed6c458530a547ed0c9ea0b02b19bab620be88b"},{"fixed":"9fefc78f7f02d71810776fdeb119a05a946a27cc"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"0"},{"last_affected":"7689ab22de36f8db19095f6bdf11f28cfde92f5c"},{"last_affected":"62d591dde4defb1333d202410609c4ddeae060b3"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-68325.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.10.248"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.198"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.160"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.120"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.63"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.17.13"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.17.0"},{"fixed":"6.18.2"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-68325.json"}}],"schema_version":"1.7.5"}