CVE-2025-21766
CVE-2025-21766 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.
Key facts
- Severity: Medium (CVSS 3.x base score 5.5)
- EPSS exploit prediction: 0% (10th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2025-5166
- Affected product: Linux Linux Kernel
- Published:
- Last modified:
Description
In the Linux kernel, the following vulnerability has been resolved: ipv4: use RCU protection in __ip_rt_update_pmtu() __ip_rt_update_pmtu() must use RCU protection to make sure the net structure it reads does not disappear.
Frequently asked questions
- What is CVE-2025-21766?
- In the Linux kernel, the following vulnerability has been resolved: ipv4: use RCU protection in __ip_rt_update_pmtu() __ip_rt_update_pmtu() must use RCU protection to make sure the net structure it reads does not disappear.
- How severe is CVE-2025-21766?
- CVE-2025-21766 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
- Is CVE-2025-21766 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (10th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2025-21766?
- CVE-2025-21766 primarily affects Linux Linux Kernel. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2025-21766?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2025-21766 have an EU (EUVD) identifier?
- Yes. CVE-2025-21766 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-5166.
- When was CVE-2025-21766 published?
- CVE-2025-21766 was published on 2025-02-27 and last updated on 2026-06-17.
References
- https://git.kernel.org/stable/c/139512191bd06f1b496117c76372b2ce372c9a41
- https://git.kernel.org/stable/c/4583748b65dee4d61bd50a2214715b4237bc152a
- https://git.kernel.org/stable/c/9b1766d1ff5fe496aabe9fc5f4e34e53f35c11c4
- https://git.kernel.org/stable/c/a39f61d212d822b3062d7f70fa0588e50e55664e
- https://git.kernel.org/stable/c/ce3c6165fce0f06305c806696882a3ad4b90e33f
- https://git.kernel.org/stable/c/ea07480b23225942208f1b754fea1e7ec486d37e
- https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html
- https://cert-portal.siemens.com/productcert/html/ssa-082556.html
Affected products (6)
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:5.9:-:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:5.9:rc7:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:5.9:rc8:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:6.14:rc2:*:*:*:*:*:*
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