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5.5
CVE-2025-21939: Linux kernel may corrupt memory when handling graphics pages
CVE-2025-21939 · published 1 year ago
Summary
The Linux kernel's graphics subsystem could access memory pages it doesn't own, potentially leading to data corruption. This happens when the system builds memory tables without holding the required lock. Updating the kernel to the latest version resolves the issue.
What to do
- Update linux kernel to version 6.13.7.
- Update debian linux to version 6.12.19-1.
- Update linux linux to version 2a24c98f0e4cc994334598d4f3a851972064809d or later.
Affected software
| Ecosystem | Vendor | Product | Affected versions |
|---|---|---|---|
| – | linux | linux_kernel |
>= 6.10, < 6.12.19 >= 6.13, < 6.13.7 6.14 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| – | linux | linux |
< 2a24c98f0e4cc994334598d4f3a851972064809d 6.10 |
| Linux | linux | kernel |
>= 6.13.0, < 6.13.7 Fix: upgrade to 6.13.7
|
| Debian:13 | debian | linux |
< 6.12.19-1 Fix: upgrade to 6.12.19-1
|
Original advisory text
drm/xe/hmm: Don't dereference struct page pointers without notifier lock
In the Linux kernel, the following vulnerability has been resolved: drm/xe/hmm: Don't dereference struct page pointers without notifier lock The pnfs that we obtain from hmm_range_fault() point to pages that we don't have a reference on, and the guarantee that they are still in the cpu page-tables is that the notifier lock must be held and the notifier seqno is still valid. So while building the sg table and marking the pages accesses / dirty we need to hold this lock with a validated seqno. However, the lock is reclaim tainted which makes sg_alloc_table_from_pages_segment() unusable, since it internally allocates memory. Instead build the sg-table manually. For the non-iommu case this might lead to fewer coalesces, but if that's a problem it can be fixed up later in the resource cursor code. For the iommu case, the whole sg-table may still be coalesced to a single contigous device va region. This avoids marking pages that we don't own dirty and accessed, and it also avoid dereferencing struct pages that we don't own. v2: - Use assert to check whether hmm pfns are valid (Matthew Auld) - Take into account that large pages may cross range boundaries (Matthew Auld) v3: - Don't unnecessarily check for a non-freed sg-table. (Matthew Auld) - Add a missing up_read() in an error path. (Matthew Auld) (cherry picked from commit ea3e66d280ce2576664a862693d1da8fd324c317)
References
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21939... Vendor Advisory
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git Product
- https://nvd.nist.gov/vuln/detail/CVE-2025-21939 Vendor Advisory
- https://git.kernel.org/stable/c/2a24c98f0e4cc994334598d4f3a851972064809d
- https://git.kernel.org/stable/c/f9326f529da7298a95643c3267f1c0fdb0db55eb
- https://git.kernel.org/stable/c/0a98219bcc961edd3388960576e4353e123b4a51
- https://security-tracker.debian.org/tracker/CVE-2025-21939 Vendor Advisory
Internet-facing
60 days
Internal
At next upgrade
- Not known to be exploited
- Needs hands-on effort to exploit (estimated)
- Gives an attacker partial control (estimated)
Type
CWE-476NULL Pointer Dereference
Timeline
Published1 Apr 2025
Updated29 Oct 2026
First seen7 Mar 2026
Sources
CVE-2025-21939 · OSV
CVE-2025-21939 · NVD
CVE-2025-21939 · MITRE
DEBIAN-CVE-2025-21939 · OSV
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