Linux Kernel: ZRAM Use-After-Free in zram_bvec_write_partial()
CVE-2026-53185 Published on June 25, 2026
zram: fix use-after-free in zram_bvec_write_partial()
In the Linux kernel, the following vulnerability has been resolved:
zram: fix use-after-free in zram_bvec_write_partial()
zram_read_page() picks the sync or async backing device read path based on
whether the parent bio is NULL. zram_bvec_write_partial() passes its
parent bio down, so for ZRAM_WB slots the read is dispatched
asynchronously and zram_read_page() returns 0 while the bio is still in
flight. The caller then runs memcpy_from_bvec(), zram_write_page() and
__free_page() on the buffer, leaving the async read to write into a freed
page.
zram_bvec_read_partial() was switched to NULL in commit 4e3c87b9421d
("zram: fix synchronous reads") for the same reason; the write_partial
counterpart was missed.
Vulnerability Analysis
CVE-2026-53185 can be exploited with local system access, and requires small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to be very high.
Weakness Type
Signal Handler Race Condition
The software uses a signal handler that introduces a race condition.
Products Associated with CVE-2026-53185
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Affected Versions
Linux:- Version 8e654f8fbff52ac483fb69957222853d7e2fc588 and below 0c2821665ff71be3f4b07ecece384669f2877f6a is affected.
- Version 8e654f8fbff52ac483fb69957222853d7e2fc588 and below 77a602b505ce4802915853cfc435a4722fab3e64 is affected.
- Version 8e654f8fbff52ac483fb69957222853d7e2fc588 and below c96786d6ff1acc1d54d9241e97767554c1dfdd5b is affected.
- Version 8e654f8fbff52ac483fb69957222853d7e2fc588 and below 198b5a14cca27263b9c14b20114c8092de15dfcb is affected.
- Version 8e654f8fbff52ac483fb69957222853d7e2fc588 and below 732fd9f0b9c1cdc6dfd77162ded60df005182cc0 is affected.
- Version 4.14 is affected.
- Before 4.14 is unaffected.
- Version 6.6.143, <= 6.6.* is unaffected.
- Version 6.12.94, <= 6.12.* is unaffected.
- Version 6.18.36, <= 6.18.* is unaffected.
- Version 7.0.13, <= 7.0.* is unaffected.
- Version 7.1, <= * is unaffected.