cve/2025/CVE-2025-21639.md

### [CVE-2025-21639](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2025-21639)
![](https://img.shields.io/static/v1?label=Product&message=Linux&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=3.13%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=4f3fdf3bc59cafd14c3bc2c2369efad34c7aa8b5%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=n%2Fa&color=blue)

### Description

In the Linux kernel, the following vulnerability has been resolved:sctp: sysctl: rto_min/max: avoid using current->nsproxyAs 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 usingcontainer_of().Note that table->data could also be used directly, as this is the onlymember needed from the 'net' structure, but that would increase the sizeof this fix, to use '*data' everywhere 'net->sctp.rto_min/max' is used.

### POC

#### Reference
No PoCs from references.

#### Github
- https://github.com/fkie-cad/nvd-json-data-feeds
- https://github.com/oogasawa/Utility-security
- https://github.com/w4zu/Debian_security