# CVE-2026-53185: zram: fix use-after-free in zram_bvec_write_partial()

> A use-after-free in the Linux kernel zram driver allows attackers to execute arbitrary code or cause a denial of service via crafted write operations.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Jun 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-90366, BELL-CVE-2026-53185, DEBIAN-CVE-2026-53185, GHSA-4pqw-3h25-qrq3, ROOT-OS-DEBIAN-11-CVE-2026-53185, ROOT-OS-DEBIAN-12-CVE-2026-53185, ROOT-OS-UBUNTU-2204-CVE-2026-53185, ROOT-OS-UBUNTU-2404-CVE-2026-53185, UBUNTU-CVE-2026-53185

## What is CVE-2026-53185?

CVE-2026-53185 is a high-severity use after free vulnerability in Linux kernel, published on 25 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

Weakness: CWE-416 (Use After Free), CWE-364 (Signal Handler Race Condition)

## Which versions are affected by CVE-2026-53185?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-53185?

Apply the vendor's patch.

## Is CVE-2026-53185 being exploited?

There is no known exploitation of CVE-2026-53185 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53185 and fix it if it is affected.

What it is: CVE-2026-53185 is a high-severity use after free vulnerability in Linux kernel, published on 25 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-53185 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-53185/ (Markdown: https://insights.sbomify.com/CVE-2026-53185/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53185
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53185
- OSV: https://osv.dev/vulnerability/CVE-2026-53185

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53185/
Summaries are generated and may contain mistakes; the official description above is the record.