# CVE-2026-57918: Integer overflow in libnfs

> A crafted NFS server can trigger an integer underflow in libnfs, potentially causing a denial of service during socket communication.

- **Severity:** High 7.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:L`)
- **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:** 26 Jun 2026
- **Updated:** 26 Jun 2026
- **Also known as:** GHSA-27p2-fpv6-cj8c, MGASA-2026-0438

## What is CVE-2026-57918?

CVE-2026-57918 is a high-severity vulnerability in sahlberg libnfs, published on 26 Jun 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

libnfs through 6.0.2 before 935b8db has an xid integer underflow in READ_IOVEC in rpc_read_from_socket in lib/socket.c during a connection to a crafted NFS server, when the expected pdu size exceeds the absolute pdu size from the xid/record-marker.

Weakness: CWE-191 (Integer Underflow (Wrap or Wraparound))

## Which versions are affected by CVE-2026-57918?


## How do I fix CVE-2026-57918?

Apply the vendor's patch.

## Is CVE-2026-57918 being exploited?

There is no known exploitation of CVE-2026-57918 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-57918 and fix it if it is affected.

What it is: CVE-2026-57918 is a high-severity vulnerability in sahlberg libnfs, published on 26 Jun 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-2026-57918 in the wild and no public exploit code.

Affected product: sahlberg libnfs. 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-2026-57918/ (Markdown: https://insights.sbomify.com/CVE-2026-57918/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-57918
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-57918
- OSV: https://osv.dev/vulnerability/CVE-2026-57918

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-57918/
Summaries are generated and may contain mistakes; the official description above is the record.