# CVE-2026-65981: Coturn: MOBILITY-TICKET session-resume authorization bypass allows cross-user TURN allocation takeover

> An authenticated attacker can hijack another user's TURN allocation by exploiting a missing identity check during session resumption with mobility tickets.

- **Severity:** High 7.1 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 31 Jul 2026
- **Updated:** 5 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-65981, GHSA-69wx-x7x6-pjj8, UBUNTU-CVE-2026-65981

## What is CVE-2026-65981?

CVE-2026-65981 is a high-severity authentication bypass vulnerability in coturn, published on 31 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.15.0, a server using --mobility authenticates a resumed REFRESH request with the resuming user's credentials but does not verify that identity against the original allocation owner, allowing an authenticated attacker who obtains a victim MOBILITY-TICKET to receive and inject relayed traffic and consume the victim's quota. In the handle_turn_refresh resume branch, the victim allocation (orig_ss) is located solely by the attacker-controlled mobile id, and credentials are only adopted (via copy_auth_parameters) when the resuming session is unauthenticated. Because the attacker's session already has hmackey_set set to 1 from its own prior authentication (which is never reset for long-term-credential sessions), the credential copy is skipped and check_stun_auth validates the REFRESH against the attacker's own identity rather than the allocation owner's. This issue is fixed in version 4.15.0.

Weakness: CWE-639 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2026-65981?


## How do I fix CVE-2026-65981?

Upgrade to a fixed version.

## Is CVE-2026-65981 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-65981 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-65981 and fix it if it is affected.

What it is: CVE-2026-65981 is a high-severity authentication bypass vulnerability in coturn, published on 31 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-65981 exists.

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-2026-65981/ (Markdown: https://insights.sbomify.com/CVE-2026-65981/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-65981
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-65981
- OSV: https://osv.dev/vulnerability/CVE-2026-65981

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-65981/
Summaries are generated and may contain mistakes; the official description above is the record.