CVE-2025-21640
7.1 · HIGHOverview
CVE-2025-21640 is a high-severity vulnerability affecting linux linux_kernel. It was published on January 19, 2025 and has a CVSS 3.1 base score of 7.1 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.1, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
Technical Description
In the Linux kernel, the following vulnerability has been resolved:
sctp: sysctl: cookie_hmac_alg: 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.sctp_hmac_alg' is
used.
Remediation
Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| linux | linux_kernel | >= 3.8, < 6.1.125 | Affected |
References
Frequently Asked Questions
What is CVE-2025-21640?
CVE-2025-21640 is a high-severity vulnerability affecting linux linux_kernel. It was published on January 19, 2025 and has a CVSS 3.1 base score of 7.1 (HIGH).
How severe is CVE-2025-21640?
This vulnerability has a CVSS 3.1 base score of 7.1, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2025-21640?
Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2025-21640?
CyberStrike's AI-powered security agents can automatically detect CVE-2025-21640 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
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