CVE-2025-21637: sctp: sysctl: udp_port: avoid using current->nsproxy
In the Linux kernel, the following vulnerability has been resolved:
sctp: sysctl: udpport: 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 5.10.223-1Fixed 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-2025-21637?
CVE-2025-21637 is classified as a moderate severity vulnerability.
How do I fix CVE-2025-21637?
To fix CVE-2025-21637, upgrade to the patched version of the Linux kernel as specified in the latest updates.
What are the potential consequences of CVE-2025-21637?
Exploitation of CVE-2025-21637 may lead to unexpected behavior in the Linux kernel, potentially affecting system stability.
Which versions of the Linux kernel are affected by CVE-2025-21637?
CVE-2025-21637 affects various versions of the Linux kernel prior to the fix being applied.
Is CVE-2025-21637 specific to certain Linux distributions?
CVE-2025-21637 can potentially affect all distributions using the vulnerable versions of the Linux kernel.