# CVE-2026-104074: Coturn 4.10.0 Uninitialized Stack Memory Disclosure via ERROR-CODE

> Remote attackers can leak stack memory via unauthenticated TURN requests, exposing pointer fragments that weaken ASLR and enable version fingerprinting.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 7 Oct 2026
- **Updated:** 27 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-104074, GHSA-6h6j-pfrh-66v3, UBUNTU-CVE-2026-104074

## What is CVE-2026-104074?

CVE-2026-104074 is a medium-severity vulnerability in coturn, published on 7 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Coturn 4.10.0 contains an uninitialized memory disclosure vulnerability that allows remote unauthenticated attackers to leak stack memory contents by sending a TURN Allocate request without credentials. Attackers can exploit the stun_init_error_response_common_str() function in src/client/ns_turn_msg.c, which fails to zero-initialize the avalue buffer before computing its length with strlen() and copying leaked stack bytes into the ERROR-CODE reason phrase, exposing pointer fragments that weaken ASLR and enable precise version fingerprinting.

Weakness: CWE-908 (Use of Uninitialized Resource)

## Which versions are affected by CVE-2026-104074?


## How do I fix CVE-2026-104074?

Apply the vendor's patch.

## Is CVE-2026-104074 being exploited?

There is no known exploitation of CVE-2026-104074 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-104074 and fix it if it is affected.

What it is: CVE-2026-104074 is a medium-severity vulnerability in coturn, published on 7 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-104074 in the wild and no public exploit code.

Affected product: coturn. 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-2026-104074/ (Markdown: https://insights.sbomify.com/CVE-2026-104074/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-104074
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-104074
- OSV: https://osv.dev/vulnerability/CVE-2026-104074

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-104074/
Summaries are generated and may contain mistakes; the official description above is the record.