CVE-2025-21638: sctp: sysctl: auth_enable: avoid using current->nsproxy
In the Linux kernel, the following vulnerability has been resolved:
sctp: sysctl: authenable: 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 containerof().
Note that table->data could also be used directly, but that would increase the size of this fix, while 'sctp.ctlsock' still needs to be retrieved from 'net' structure.
Other sources
This CVE was automatically created from a reference found in an email or other text. If you are reading this, then this CVE entry is probably erroneous, since this text should be replaced by the official CVE description automatically.
— Launchpad
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
debian/linuxto a version that resolves this vulnerability.Fixed in 5.10.234-1Fixed in 6.1.129-1Fixed in 6.1.135-1Fixed in 6.12.27-1 - Upgrade
Upgrade
debian/linux-6.1to a version that resolves this vulnerability.Fixed in 6.1.129-1~deb11u1 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 5.15.180.1-1 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 6.6.78.1-3
Event History
Frequently Asked Questions
What is the severity of CVE-2025-21638?
CVE-2025-21638 is considered a medium severity vulnerability in the Linux kernel.
How do I fix CVE-2025-21638?
To fix CVE-2025-21638, ensure your Linux kernel is updated to the latest patched version provided by your distribution.
What are the potential impacts of CVE-2025-21638?
CVE-2025-21638 may lead to inconsistencies in network processing due to improper use of the current context in the SCTP protocol.
Which versions of the Linux kernel are affected by CVE-2025-21638?
CVE-2025-21638 affects multiple versions of the Linux kernel prior to the fix being applied.
Is CVE-2025-21638 related to network security?
Yes, CVE-2025-21638 is related to network security as it involves the SCTP protocol management within the Linux kernel.