Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
Linux Linux — drm/xe/hmm: Don't dereference struct page pointers without notifier lock
AV AC PR UI S C I A CVSS EPSS %ile KEV
L L L N U N N H 5.5 .0020 10.4 —
AFFECTED
Product Versions Fixed
Linux 81e058a3e7fd8593d076b4f26f7b8bb49f1d61e3 – —
Linux 6.10 – 6.12.19
TIMELINE
Dec 29 Reserved by Linux
Apr 1 Published (CNA: Linux)
Jul 30 RESCORED — CVE-2025-21939 (Linux). CVSS 7.8 → 5.5 (NVD).
Description
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)
Lifecycle
Complete event history — 3 events, chronological
| Date | Event | Detail |
| December 29, 2024 | Reserved | Reserved by Linux |
| April 1, 2025 | Published | Published (CNA: Linux) |
| July 30, 2026 | RESCORED | RESCORED — CVE-2025-21939 (Linux). CVSS 7.8 → 5.5 (NVD). |
Affected
Affected products and packages — 2 rows
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
| Linux | Linux | — | 81e058a3e7fd8593d076b4f26f7b8bb49f1d61e3 | — |
| Linux | Linux | — | 6.10 | 6.12.19 |
About this page
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2025-21939 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.