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.
References
Configurations
Configuration 1 (hide)
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History
14 Jul 2026, 13:18
| Type | Values Removed | Values Added |
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| References |
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06 May 2026, 21:23
| Type | Values Removed | Values Added |
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| CPE | cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:* |
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| CWE | NVD-CWE-noinfo | |
| First Time |
Linux
Linux linux Kernel |
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| References | () https://git.kernel.org/stable/c/3c54b66c83fb8fcbde8e6a7bf90b65856e39f827 - Patch | |
| References | () https://git.kernel.org/stable/c/414726b69921fe6355ae453f5b35e68dd078342a - Patch | |
| References | () https://git.kernel.org/stable/c/4b6798024f7b2d535f3db1002c760143cdbd1bd3 - Patch | |
| References | () https://git.kernel.org/stable/c/572ce62778519a7d4d1c15f55dd2e45a474133c4 - Patch | |
| References | () https://git.kernel.org/stable/c/5a6b15f861b7c1304949e3350d23490a5fe429fd - Patch | |
| References | () https://git.kernel.org/stable/c/6c7fbdb8ffde6413640de7cfbd7c976c353e89f8 - Patch | |
| References | () https://git.kernel.org/stable/c/8027964931785cb73d520ac70a342a3dc16c249b - Patch | |
| References | () https://git.kernel.org/stable/c/9ca562bb8e66978b53028fa32b1a190708e6a091 - Patch |
27 Apr 2026, 15:16
| Type | Values Removed | Values Added |
|---|---|---|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 7.8 |
25 Apr 2026, 09:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-04-25 09:16
Updated : 2026-07-14 13:18
NVD link : CVE-2026-31680
Mitre link : CVE-2026-31680
CVE.ORG link : CVE-2026-31680
JSON object : View
Products Affected
linux
- linux_kernel
CWE
