CVE-2026-31680
Essential information
- Published
- 25/04/2026 09:16
- Modified
- 25/04/2026 09:16
- Author
- —
- Creator
- —
- CISA KEV
- No
- CWE
- —
- CVSS vector
- — — —
Description
In the Linux kernel, the following vulnerability has been resolved:
net: ipv6: flowlabel: defer exclusive option free until RCU teardown
`ip6fl_seq_show()` walks the global flowlabel hash under the seq-file
RCU read-side lock and prints `fl->opt->opt_nflen` when an option block
is present.
Exclusive flowlabels currently free `fl->opt` as soon as `fl->users`
drops to zero in `fl_release()`. However, the surrounding
`struct ip6_flowlabel` remains visible in the global hash table until
later garbage collection removes it and `fl_free_rcu()` finally tears it
down.
A concurrent `/proc/net/ip6_flowlabel` reader can therefore race that
early `kfree()` and dereference freed option state, triggering a crash
in `ip6fl_seq_show()`.
Fix this by keeping `fl->opt` alive until `fl_free_rcu()`. That matches
the lifetime already required for the enclosing flowlabel while readers
can still reach it under RCU.
NVD status
- Status
- Received — CVE has been recently published to the CVE List and has been received by the NVD.
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- NVD
- View on NVD
Affected products (CPE)
| Product | CPE |
|---|---|
| linux / linux kernel | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |