Description
In the Linux kernel, the following vulnerability has been resolved: net/sched: Make cake_enqueue return NET_XMIT_CN when past buffer_limit The following setup can trigger a WARNING in htb_activate due to the condition: !cl->leaf.q->q.qlen tc qdisc del dev lo root tc qdisc add dev lo root handle 1: htb default 1 tc class add dev lo parent 1: classid 1:1 \ htb rate 64bit tc qdisc add dev lo parent 1:1 handle f: \ cake memlimit 1b ping -I lo -f -c1 -s64 -W0.001 127.0.0.1 This is because the low memlimit leads to a low buffer_limit, which causes packet dropping. However, cake_enqueue still returns NET_XMIT_SUCCESS, causing htb_enqueue to call htb_activate with an empty child qdisc. We should return NET_XMIT_CN when packets are dropped from the same tin and flow. I do not believe return value of NET_XMIT_CN is necessary for packet drops in the case of ack filtering, as that is meant to optimize performance, not to signal congestion.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
046f6fd5daefac7f5abdafb436b30f63bc7c602b to < 7689ab22de36f8db19095f6bdf11f28cfde92f5caffected046f6fd5daefac7f5abdafb436b30f63bc7c602b to < de04ddd2980b48caa8d7e24a7db2742917a8b280affected046f6fd5daefac7f5abdafb436b30f63bc7c602b to < 0dacfc5372e314d1219f03e64dde3ab495a5a25eaffected046f6fd5daefac7f5abdafb436b30f63bc7c602b to < 710866fc0a64eafcb8bacd91bcb1329eb7e5035faffected046f6fd5daefac7f5abdafb436b30f63bc7c602b to < aa12ee1c1bd260943fd6ab556d8635811c332eebaffected046f6fd5daefac7f5abdafb436b30f63bc7c602b to < ff57186b2cc39766672c4c0332323933e5faaa88affected046f6fd5daefac7f5abdafb436b30f63bc7c602b to < 62d591dde4defb1333d202410609c4ddeae060b3affected046f6fd5daefac7f5abdafb436b30f63bc7c602b to < 15de71d06a400f7fdc15bf377a2552b0ec437cf5affected
Linux Linux
Default version status: affected
4.19affected0 to < 4.19unaffected5.4.297 to ≤ 5.4.*unaffected5.10.241 to ≤ 5.10.*unaffected5.15.190 to ≤ 5.15.*unaffected6.1.149 to ≤ 6.1.*unaffected6.6.103 to ≤ 6.6.*unaffected6.12.44 to ≤ 6.12.*unaffected6.16.4 to ≤ 6.16.*unaffected6.17 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/7689ab22de36f8db19095f6bdf11f28cfde92f5c ↗
- https://git.kernel.org/stable/c/de04ddd2980b48caa8d7e24a7db2742917a8b280 ↗
- https://git.kernel.org/stable/c/0dacfc5372e314d1219f03e64dde3ab495a5a25e ↗
- https://git.kernel.org/stable/c/710866fc0a64eafcb8bacd91bcb1329eb7e5035f ↗
- https://git.kernel.org/stable/c/aa12ee1c1bd260943fd6ab556d8635811c332eeb ↗
- https://git.kernel.org/stable/c/ff57186b2cc39766672c4c0332323933e5faaa88 ↗
- https://git.kernel.org/stable/c/62d591dde4defb1333d202410609c4ddeae060b3 ↗
- https://git.kernel.org/stable/c/15de71d06a400f7fdc15bf377a2552b0ec437cf5 ↗
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html ↗
- https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html ↗
- https://cert-portal.siemens.com/productcert/html/ssa-032379.html ↗