# CVE-2026-31435: netfs: Fix read abandonment during retry

> A null pointer dereference in the Linux kernel netfs subsystem can cause a system crash during read request retries.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 22 Apr 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-31435, DEBIAN-CVE-2026-31435, GHSA-qfvq-ggc7-jqgw, ROOT-OS-DEBIAN-13-CVE-2026-31435, UBUNTU-CVE-2026-31435

## What is CVE-2026-31435?

CVE-2026-31435 is a high-severity vulnerability in Linux kernel, published on 22 Apr 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

netfs: Fix read abandonment during retry

Under certain circumstances, all the remaining subrequests from a read
request will get abandoned during retry.  The abandonment process expects
the 'subreq' variable to be set to the place to start abandonment from, but
it doesn't always have a useful value (it will be uninitialised on the
first pass through the loop and it may point to a deleted subrequest on
later passes).

Fix the first jump to "abandon:" to set subreq to the start of the first
subrequest expected to need retry (which, in this abandonment case, turned
out unexpectedly to no longer have NEED_RETRY set).

Also clear the subreq pointer after discarding superfluous retryable
subrequests to cause an oops if we do try to access it.

Weakness: CWE-125 (Out-of-bounds Read), CWE-457 (Use of Uninitialized Variable)

## Which versions are affected by CVE-2026-31435?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-31435?

Apply the vendor's patch.

## Is CVE-2026-31435 being exploited?

There is no known exploitation of CVE-2026-31435 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-2026-31435 and fix it if it is affected.

What it is: CVE-2026-31435 is a high-severity vulnerability in Linux kernel, published on 22 Apr 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-31435 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-2026-31435/ (Markdown: https://insights.sbomify.com/CVE-2026-31435/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31435
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31435
- OSV: https://osv.dev/vulnerability/CVE-2026-31435

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31435/
Summaries are generated and may contain mistakes; the official description above is the record.