# CVE-2026-55759: Rocket.Chat: Apple Sign-In skips JWT claims validation, allowing expired and cross-audience token replay

> Attackers can replay expired or cross-audience Apple identity tokens to authenticate as users due to missing JWT claims validation in Rocket.Chat.

- **Severity:** High 7.4 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 24 Jun 2026
- **Updated:** 26 Jun 2026
- **Also known as:** GHSA-c75c-5hc7-j4vp

## What is CVE-2026-55759?

CVE-2026-55759 is a high-severity authentication bypass vulnerability in RocketChat Rocket.Chat, published on 24 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Rocket.Chat is an open-source, secure, fully customizable communications platform. Prior to 8.5.1, 8.4.4, 8.3.6, 8.2.6, 8.1.6, 8.0.7, and 7.10.13, Rocket.Chat's Apple Sign-In handler verifies JWT signatures but skips claims validation. Any Apple-signed JWT with a non-empty iss is accepted regardless of aud, exp, nbf, or nonce. An attacker who obtains a target user's Apple identity token (from server logs, an intercepted sign-in flow, or another application sharing the same Apple developer team) can replay it to authenticate as that user, with no expiration on the replay window. This vulnerability is fixed in 8.5.1, 8.4.4, 8.3.6, 8.2.6, 8.1.6, 8.0.7, and 7.10.13.

Weakness: CWE-294 (Authentication Bypass by Capture-replay), CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2026-55759?


## How do I fix CVE-2026-55759?

No fix has been published for CVE-2026-55759 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-55759 being exploited?

There is no known exploitation of CVE-2026-55759 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-55759 and fix it if it is affected.

What it is: CVE-2026-55759 is a high-severity authentication bypass vulnerability in RocketChat Rocket.Chat, published on 24 Jun 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-2026-55759 in the wild and no public exploit code.

Affected product: RocketChat Rocket.Chat. 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-2026-55759/ (Markdown: https://insights.sbomify.com/CVE-2026-55759/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-55759
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-55759
- OSV: https://osv.dev/vulnerability/CVE-2026-55759

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-55759/
Summaries are generated and may contain mistakes; the official description above is the record.