5.5

CVE-2025-71080

ipv6: fix a BUG in rt6_get_pcpu_route() under PREEMPT_RT

In the Linux kernel, the following vulnerability has been resolved:

ipv6: fix a BUG in rt6_get_pcpu_route() under PREEMPT_RT

On PREEMPT_RT kernels, after rt6_get_pcpu_route() returns NULL, the
current task can be preempted. Another task running on the same CPU
may then execute rt6_make_pcpu_route() and successfully install a
pcpu_rt entry. When the first task resumes execution, its cmpxchg()
in rt6_make_pcpu_route() will fail because rt6i_pcpu is no longer
NULL, triggering the BUG_ON(prev). It's easy to reproduce it by adding
mdelay() after rt6_get_pcpu_route().

Using preempt_disable/enable is not appropriate here because
ip6_rt_pcpu_alloc() may sleep.

Fix this by handling the cmpxchg() failure gracefully on PREEMPT_RT:
free our allocation and return the existing pcpu_rt installed by
another task. The BUG_ON is replaced by WARN_ON_ONCE for non-PREEMPT_RT
kernels where such races should not occur.
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Linux ≫ Linux Kernel Version >= 6.12.1 < 6.12.64
Linux ≫ Linux Kernel Version >= 6.13 < 6.18.4
Linux ≫ Linux Kernel Version 6.12 Update -
Linux ≫ Linux Kernel Version 6.19 Update rc1
Linux ≫ Linux Kernel Version 6.19 Update rc2
Linux ≫ Linux Kernel Version 6.19 Update rc3
Linux ≫ Linux Kernel Version 6.19 Update rc4
Linux ≫ Linux Kernel Version 6.19 Update rc5
Linux ≫ Linux Kernel Version 6.19 Update rc6
Linux ≫ Linux Kernel Version 6.19 Update rc7
Linux ≫ Linux Kernel Version 6.19 Update rc8
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.26% 0.182
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
NIST 5.5 1.8 3.6
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
416baaa9-dc9f-4396-8d5f-8c081fb06d67 7.5 3.9 3.6
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE-617 Reachable Assertion

The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.

https://git.kernel.org/stable/c/1dc33ad0867325f8d2c6d7b2a6f542d4f3121f66
Patch
https://git.kernel.org/stable/c/787515ccb2292f82eb0876993129154629a49651
Patch
https://git.kernel.org/stable/c/1adaea51c61b52e24e7ab38f7d3eba023b2d050d
Patch