CVE-2026-97958EPSS p6.5%
CVE-2026-97958CVE-2026-97958
Description
In the Linux kernel, the following vulnerability has been resolved:
net/sched: cls_api: Don't replay RTM_GETCHAIN in tc_ctl_chain().
If a netlink socket sends RTM_GETCHAIN requests repeatedly
without recv()ing the responses, tc_ctl_chain() hogs CPU and
triggers Hung Task splat. [0]
As caught in the stack trace, netlink_attachskb() could confuse
tc_ctl_chain() by returning -EAGAIN when the userspace netlink
socket's receive buffer is full.
The replay: label exists since commit 32a4f5ecd738 ("net: sched:
introduce chain object to uapi") but was not used initially.
Since commit 9f407f1768d3 ("net: sched: introduce chain templates"),
the label is needed for RTM_NEWCHAIN because tcf_proto_lookup_ops()
may release RTNL to call request_module().
However, the replay logic is unnecessary for RTM_GETCHAIN.
Let's apply the replay logic only for RTM_NEWCHAIN.
[0]:
INFO: task repro:1018 is blocked on a mutex likely owned by task repro:1022.
task:repro state:R running task sta
Scoring
| EPSS | 0.18% probability of exploitation · percentile 6.5% · 2026-10-05T12:00:23Z |
| Last modified | 2026-10-03 |