{"id":"CVE-2025-68815","title":"net/sched: ets: Remove drr class from the active list if it changes to strict","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: ets: Remove drr class from the active list if it changes to strict\n\nWhenever a user issues an ets qdisc change command, transforming a\ndrr class into a stric…","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","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= f517335a61ff8037b18ba1b0a002c1f82926a934 < 58fdce6bc005e964f1dbc3ca716f5fe0f68839a2","Linux >= cd9b50adc6bb9ad3f7d244590a389522215865c4 < 02783a37cb1c0a2bd9fcba4ff1b81e6e209c7d87","Linux >= cd9b50adc6bb9ad3f7d244590a389522215865c4 < 8067db5c95aab9461d23117679338cd8869831fa","Linux >= cd9b50adc6bb9ad3f7d244590a389522215865c4 < 2f125ebe47d6369e562f3cbd9b6227cff51eaf34","Linux >= cd9b50adc6bb9ad3f7d244590a389522215865c4 < cca2ed931b734fe48139bc6f020e47367346630f","Linux >= cd9b50adc6bb9ad3f7d244590a389522215865c4 < 43d9a530c8c094d137159784e7c951c65f11ec6c","Linux >= cd9b50adc6bb9ad3f7d244590a389522215865c4 < b1e125ae425aba9b45252e933ca8df52a843ec70","Linux d05330672afe2e142ba97e63bd7c1faef76781bb","Linux >= 5.10.62 < 5.10.248","Linux >= 5.13.14 < 5.14","Linux 5.14"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-16T15:05:26.883019Z"},"published":"2026-01-13","updated":"2026-10-16","sourceUpdated":"2026-10-16T15:09:45.457Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-68815","references":[{"url":"https://git.kernel.org/stable/c/58fdce6bc005e964f1dbc3ca716f5fe0f68839a2"},{"url":"https://git.kernel.org/stable/c/02783a37cb1c0a2bd9fcba4ff1b81e6e209c7d87"},{"url":"https://git.kernel.org/stable/c/8067db5c95aab9461d23117679338cd8869831fa"},{"url":"https://git.kernel.org/stable/c/2f125ebe47d6369e562f3cbd9b6227cff51eaf34"},{"url":"https://git.kernel.org/stable/c/cca2ed931b734fe48139bc6f020e47367346630f"},{"url":"https://git.kernel.org/stable/c/43d9a530c8c094d137159784e7c951c65f11ec6c"},{"url":"https://git.kernel.org/stable/c/b1e125ae425aba9b45252e933ca8df52a843ec70"}],"tags":["cve.org"],"epss":0.00155,"epssPercentile":0.04184,"ingestedAt":"2026-10-16T17:24:46.634Z","slug":"CVE-2025-68815","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: ets: Remove drr class from the active list if it changes to strict\n\nWhenever a user issues an ets qdisc change command, transforming a\ndrr class into a strict one, the ets code isn't checking whether that\nclass was in the active list and removing it. This means that, if a\nuser changes a strict class (which was in the active list) back to a drr\none, that class will be added twice to the active list [1].\n\nDoing so with the following commands:\n\ntc qdisc add dev lo root handle 1: ets bands 2 strict 1\ntc qdisc add dev lo parent 1:2 handle 20: \\\n    tbf rate 8bit burst 100b latency 1s\ntc filter add dev lo parent 1: basic classid 1:2\nping -c1 -W0.01 -s 56 127.0.0.1\ntc qdisc change dev lo root handle 1: ets bands 2 strict 2\ntc qdisc change dev lo root handle 1: ets bands 2 strict 1\nping -c1 -W0.01 -s 56 127.0.0.1\n\nWill trigger the following splat with list debug turned on:\n\n[   59.279014][  T365] ------------[ cut here ]------------\n[   59.279452][  T365] list_add double add: new=ffff88801d60e350, prev=ffff88801d60e350, next=ffff88801d60e2c0.\n[   59.280153][  T365] WARNING: CPU: 3 PID: 365 at lib/list_debug.c:35 __list_add_valid_or_report+0x17f/0x220\n[   59.280860][  T365] Modules linked in:\n[   59.281165][  T365] CPU: 3 UID: 0 PID: 365 Comm: tc Not tainted 6.18.0-rc7-00105-g7e9f13163c13-dirty #239 PREEMPT(voluntary)\n[   59.281977][  T365] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011\n[   59.282391][  T365] RIP: 0010:__list_add_valid_or_report+0x17f/0x220\n[   59.282842][  T365] Code: 89 c6 e8 d4 b7 0d ff 90 0f 0b 90 90 31 c0 e9 31 ff ff ff 90 48 c7 c7 e0 a0 22 9f 48 89 f2 48 89 c1 4c 89 c6 e8 b2 b7 0d ff 90 <0f> 0b 90 90 31 c0 e9 0f ff ff ff 48 89 f7 48 89 44 24 10 4c 89 44\n...\n[   59.288812][  T365] Call Trace:\n[   59.289056][  T365]  <TASK>\n[   59.289224][  T365]  ? srso_alias_return_thunk+0x5/0xfbef5\n[   59.289546][  T365]  ets_qdisc_change+0xd2b/0x1e80\n[   59.289891][  T365]  ? __lock_acquire+0x7e7/0x1be0\n[   59.290223][  T365]  ? __pfx_ets_qdisc_change+0x10/0x10\n[   59.290546][  T365]  ? srso_alias_return_thunk+0x5/0xfbef5\n[   59.290898][  T365]  ? __mutex_trylock_common+0xda/0x240\n[   59.291228][  T365]  ? __pfx___mutex_trylock_common+0x10/0x10\n[   59.291655][  T365]  ? srso_alias_return_thunk+0x5/0xfbef5\n[   59.291993][  T365]  ? srso_alias_return_thunk+0x5/0xfbef5\n[   59.292313][  T365]  ? trace_contention_end+0xc8/0x110\n[   59.292656][  T365]  ? srso_alias_return_thunk+0x5/0xfbef5\n[   59.293022][  T365]  ? srso_alias_return_thunk+0x5/0xfbef5\n[   59.293351][  T365]  tc_modify_qdisc+0x63a/0x1cf0\n\nFix this by always checking and removing an ets class from the active list\nwhen changing it to strict.\n\n[1] https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/tree/net/sched/sch_ets.c?id=ce052b9402e461a9aded599f5b47e76bc727f7de#n663\n\n## Affected\n\n- `Linux >= f517335a61ff8037b18ba1b0a002c1f82926a934 < 58fdce6bc005e964f1dbc3ca716f5fe0f68839a2`\n- `Linux >= cd9b50adc6bb9ad3f7d244590a389522215865c4 < 02783a37cb1c0a2bd9fcba4ff1b81e6e209c7d87`\n- `Linux >= cd9b50adc6bb9ad3f7d244590a389522215865c4 < 8067db5c95aab9461d23117679338cd8869831fa`\n- `Linux >= cd9b50adc6bb9ad3f7d244590a389522215865c4 < 2f125ebe47d6369e562f3cbd9b6227cff51eaf34`\n- `Linux >= cd9b50adc6bb9ad3f7d244590a389522215865c4 < cca2ed931b734fe48139bc6f020e47367346630f`\n- `Linux >= cd9b50adc6bb9ad3f7d244590a389522215865c4 < 43d9a530c8c094d137159784e7c951c65f11ec6c`\n- `Linux >= cd9b50adc6bb9ad3f7d244590a389522215865c4 < b1e125ae425aba9b45252e933ca8df52a843ec70`\n- `Linux d05330672afe2e142ba97e63bd7c1faef76781bb`\n- `Linux >= 5.10.62 < 5.10.248`\n- `Linux >= 5.13.14 < 5.14`\n- `Linux 5.14`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}