# GHSA-w67g-5rqw-f597: Gorilla WebSocket Uses Cryptographically Weak PRNG for WebSocket Mask Key

> Attackers can predict WebSocket mask keys due to weak PRNG usage, enabling frame content injection in Go applications using Gorilla WebSocket.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Aug 2026
- **Also known as:** GO-2026-6278

## What is GHSA-w67g-5rqw-f597?

GHSA-w67g-5rqw-f597 is a vulnerability in github.com/gorilla/websocket, published on 24 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

gorilla/websocket used `math/rand` (cryptographically weak pseudo-random number generator) to generate WebSocket frame mask keys prior to commit d67f4185. WebSocket masking keys MUST be unpredictable to prevent frame content injection attacks. math/rand produces deterministic output when seeded with a known value, enabling an attacker to predict or recover mask keys and inject content into WebSocket connections.

**Type:** Use of Cryptographically Weak Pseudo-Random Number Generator
**Fix:** Replaced math/rand with crypto/rand (commit d67f4185, released in v1.5.3)
**Credit:** bounty-hunter v6.0 silent-fix detection

## Which versions are affected by GHSA-w67g-5rqw-f597?

3 open source packages ship an affected version, including github.com/gorilla/websocket.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/gorilla/websocket` | Go | All versions | 1.5.3 |
| `github.com/gorilla/websocket` | Go | All versions | 1.5.3 |
| `github.com/gorilla/websocket` | Go | All versions | 1.5.3 |

## How do I fix GHSA-w67g-5rqw-f597?

Upgrade github.com/gorilla/websocket to 1.5.3 or later.

## Is GHSA-w67g-5rqw-f597 being exploited?

There is no known exploitation of GHSA-w67g-5rqw-f597 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-w67g-5rqw-f597 and fix it if it is affected.

What it is: GHSA-w67g-5rqw-f597 is a vulnerability in github.com/gorilla/websocket, published on 24 Aug 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 GHSA-w67g-5rqw-f597 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/gorilla/websocket (Go): affected all versions; fixed in 1.5.3
- github.com/gorilla/websocket (Go): affected all versions; fixed in 1.5.3
- github.com/gorilla/websocket (Go): affected all versions; fixed in 1.5.3

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/GHSA-w67g-5rqw-f597/ (Markdown: https://insights.sbomify.com/GHSA-w67g-5rqw-f597/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-w67g-5rqw-f597

---
From sbomify Insights: https://insights.sbomify.com/GHSA-w67g-5rqw-f597/
Summaries are generated and may contain mistakes; the official description above is the record.