# CVE-2026-18370: Heap-based buffer overflow in entr

> A local attacker can trigger a heap-based buffer overflow in entr via command-line arguments, causing memory corruption and denial of service.

- **Severity:** Medium 4.8 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N`)
- **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:** 10 Aug 2026
- **Updated:** 10 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-18370, GHSA-qpgw-rgmq-2367, OESA-2026-3486, OESA-2026-3487, OESA-2026-3488, UBUNTU-CVE-2026-18370

## What is CVE-2026-18370?

CVE-2026-18370 is a medium-severity memory corruption vulnerability in eradman entr, published on 10 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

entr is vulnerable to Heap-based buffer overflow in run_utility() function. The function allocates a fixed-size heap buffer using malloc(ARG_MAX) and copies command-line arguments into it. It advances the destination pointer based on the return value of strlcpy(), which returns the total length of the source string rather than the number of bytes written. When the buffer is exactly filled, the remaining size underflows as an unsigned size_t, causing subsequent copies to write out of bounds. This can be triggered by supplying command-line arguments whose combined length fills the buffer, or via the /_ substitution feature which expands a short token into a longer pathname at runtime. The local attacker can cause memory corruption, process abort, and denial of service. 

This issue was fixed in commit 2467fe0

Weakness: CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2026-18370?


## How do I fix CVE-2026-18370?

Apply the vendor's patch.

## Is CVE-2026-18370 being exploited?

There is no known exploitation of CVE-2026-18370 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-18370 and fix it if it is affected.

What it is: CVE-2026-18370 is a medium-severity memory corruption vulnerability in eradman entr, published on 10 Aug 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-2026-18370 in the wild and no public exploit code.

Affected product: eradman entr. 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-2026-18370/ (Markdown: https://insights.sbomify.com/CVE-2026-18370/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-18370
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-18370
- OSV: https://osv.dev/vulnerability/CVE-2026-18370

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-18370/
Summaries are generated and may contain mistakes; the official description above is the record.