CVE-2025-21811
CVE-2025-21811 is a high-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-416.
Key facts
- Severity: High (CVSS 3.x base score 7.8)
- EPSS exploit prediction: 0% (12th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2025-5976
- Weakness: CWE-416
- Affected product: Linux Linux Kernel
- Published:
- Last modified:
Description
In the Linux kernel, the following vulnerability has been resolved: nilfs2: protect access to buffers with no active references nilfs_lookup_dirty_data_buffers(), which iterates through the buffers attached to dirty data folios/pages, accesses the attached buffers without locking the folios/pages. For data cache, nilfs_clear_folio_dirty() may be called asynchronously when the file system degenerates to read only, so nilfs_lookup_dirty_data_buffers() still has the potential to cause use after free issues when buffers lose the protection of their dirty state midway due to this asynchronous clearing and are unintentionally freed by try_to_free_buffers(). Eliminate this race issue by adjusting the lock section in this function.
Frequently asked questions
- What is CVE-2025-21811?
- In the Linux kernel, the following vulnerability has been resolved: nilfs2: protect access to buffers with no active references nilfs_lookup_dirty_data_buffers(), which iterates through the buffers attached to dirty data folios/pages, accesses the attached buffers without locking the folios/pages. For data cache, nilfs_clear_folio_dirty() may be called asynchronously when the file system degenerates to read only, so nilfs_lookup_dirty_data_buffers() still has the potential to cause use after free issues when buffers lose the protection of their dirty state midway due to this asynchronous clearing and are unintentionally freed by try_to_free_buffers(). Eliminate this race issue by adjusting the lock section in this function.
- How severe is CVE-2025-21811?
- CVE-2025-21811 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2025-21811 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2025-21811?
- CVE-2025-21811 affects Linux Linux Kernel. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2025-21811?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2025-21811 have an EU (EUVD) identifier?
- Yes. CVE-2025-21811 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-5976.
- When was CVE-2025-21811 published?
- CVE-2025-21811 was published on 2025-02-27 and last updated on 2026-06-17.
References
- https://git.kernel.org/stable/c/367a9bffabe08c04f6d725032cce3d891b2b9e1a
- https://git.kernel.org/stable/c/4b08d23d7d1917bef4fbee8ad81372f49b006656
- https://git.kernel.org/stable/c/58c27fa7a610b6e8d44e6220e7dbddfbaccaf439
- https://git.kernel.org/stable/c/72cf688d0ce7e642b12ddc9b2a42524737ec1b4a
- https://git.kernel.org/stable/c/8e1b9201c9a24638cf09c6e1c9f224157328010b
- https://git.kernel.org/stable/c/c437dfac9f7a5a46ac2a5e6d6acd3059e9f68188
- https://git.kernel.org/stable/c/d8ff250e085a4c4cdda4ad1cdd234ed110393143
- https://git.kernel.org/stable/c/e1fc4a90a90ea8514246c45435662531975937d9
- https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html
- https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html
Affected products (1)
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
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