CVE-2025-21636: sctp: sysctl: plpmtud_probe_interval: avoid using current->nsproxy
First published: Sun Jan 19 2025(Updated: )
In the Linux kernel, the following vulnerability has been resolved: sctp: sysctl: plpmtud_probe_interval: avoid using current->nsproxy As mentioned in a previous commit of this series, using the 'net' structure via 'current' is not recommended for different reasons: - Inconsistency: getting info from the reader's/writer's netns vs only from the opener's netns. - current->nsproxy can be NULL in some cases, resulting in an 'Oops' (null-ptr-deref), e.g. when the current task is exiting, as spotted by syzbot [1] using acct(2). The 'net' structure can be obtained from the table->data using container_of(). Note that table->data could also be used directly, as this is the only member needed from the 'net' structure, but that would increase the size of this fix, to use '*data' everywhere 'net->sctp.probe_interval' is used.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Kernel | ||
| Linux Kernel | >=5.14<5.15.177 | |
| Linux Kernel | >=5.16<6.1.125 | |
| Linux Kernel | >=6.2<6.6.72 | |
| Linux Kernel | >=6.7<6.12.10 | |
| Linux Kernel | =6.13-rc1 | |
| Linux Kernel | =6.13-rc2 | |
| Linux Kernel | =6.13-rc3 | |
| Linux Kernel | =6.13-rc4 | |
| Linux Kernel | =6.13-rc5 | |
| Linux Kernel | =6.13-rc6 |
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Reference Links
- https://git.kernel.org/stable/c/44ee8635922b6eb940faddb961a8347c6857d722
- https://git.kernel.org/stable/c/284a221f8fa503628432c7bb5108277c688c6ffa
- https://git.kernel.org/stable/c/bcf8c60074e81ed2ac2d35130917175a3949c917
- https://git.kernel.org/stable/c/6259d2484d0ceff42245d1f09cc8cb6ee72d847a
- https://git.kernel.org/stable/c/1dc5da6c4178f3e4b95c631418f72de9f86c0449
Frequently Asked Questions
What is the severity of CVE-2025-21636?
CVE-2025-21636 is classified as a low severity vulnerability in the Linux kernel.
How do I fix CVE-2025-21636?
To fix CVE-2025-21636, upgrade to the latest version of the Linux kernel that contains the patches.
What systems are affected by CVE-2025-21636?
CVE-2025-21636 affects all versions of the Linux kernel where the specific vulnerability is present.
What is the nature of the vulnerability described in CVE-2025-21636?
CVE-2025-21636 involves using the 'net' structure via 'current', which is not recommended due to potential inconsistencies.
Is there an exploit available for CVE-2025-21636?
As of now, there is no publicly known exploit for CVE-2025-21636.
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