---
title: "CVE-2025-25292: Ruby SAML allows a SAML authentication bypass due to namespace handling (parser differential)"
url: https://erroneo.us/security/cve/CVE-2025-25292/
description: "CVE-2025-25292 (ruby-saml (RubyGems)): ruby-saml provides security assertion markup language (SAML) single sign-on (SSO) for Ruby. An authentication bypass…"
type: vulnerability-record
section: "Security Digest"
date_published: 2025-03-12
date_modified: 2025-11-03
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2025-25292"
kev: false
cvss: 9.3
epss: 0.65086
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2025-25292: Ruby SAML allows a SAML authentication bypass due to namespace handling (parser differential)

**Signal:** High exploit likelihood. EPSS ranks it in the top 5% of all CVEs for likely exploitation in the next 30 days. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 65.1% , percentile 99: FIRST’s model estimates a 65.1% chance of exploitation activity in the next 30 days, higher than 99% of all scored CVEs (very high). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes ruby-saml (RubyGems) >= 1.13.0, < 1.18.0, fixed in 1.18.0 ; ruby-saml (RubyGems) < 1.12.4, fixed in 1.12.4 . Check your lockfile, including transitive dependencies.

## What it is

ruby-saml provides security assertion markup language (SAML) single sign-on (SSO) for Ruby. An authentication bypass vulnerability was found in ruby-saml prior to versions 1.12.4 and 1.18.0 due to a parser differential. ReXML and Nokogiri parse XML differently, the parsers can generate entirely different document structures from the same XML input. That allows an attacker to be able to execute a Signature Wrapping attack. This issue may lead to authentication bypass. Versions 1.12.4 and 1.18.0 contain a patch for the issue.

## Affected packages

- RubyGems `ruby-saml` >= 1.13.0, < 1.18.0 → fixed: 1.18.0
- RubyGems `ruby-saml` < 1.12.4 → fixed: 1.12.4

## Affected products (CVE record)

- SAML-Toolkits ruby-saml: < 1.12.4, >= 1.13.0, < 1.18.0

## Severity

- GitHub_M CVSS 4.0: 9.3 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N`
- GitHub CVSS 4.0: 9.3 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 65.09% probability of exploitation activity in the next 30 days; percentile 99.

## Sources

- [GitHub Advisory GHSA-754f-8gm6-c4r2](https://github.com/advisories/GHSA-754f-8gm6-c4r2)
- [CVE.org record CVE-2025-25292](https://www.cve.org/CVERecord?id=CVE-2025-25292)
- [NVD entry CVE-2025-25292](https://nvd.nist.gov/vuln/detail/CVE-2025-25292)
- [github.com](https://github.com/SAML-Toolkits/ruby-saml/security/advisories/GHSA-754f-8gm6-c4r2)
- [github.com](https://github.com/omniauth/omniauth-saml/security/advisories/GHSA-hw46-3hmr-x9xv)
- [github.com](https://github.com/SAML-Toolkits/ruby-saml/commit/e76c5b36bac40aedbf1ba7ffaaf495be63328cd9)
- [github.com](https://github.com/SAML-Toolkits/ruby-saml/commit/e9c1cdbd0f9afa467b585de279db0cbd0fb8ae97)
- [about.gitlab.com](https://about.gitlab.com/releases/2025/03/12/patch-release-gitlab-17-9-2-released)
- [github.blog](https://github.blog/security/sign-in-as-anyone-bypassing-saml-sso-authentication-with-parser-differentials)
- [github.com](https://github.com/SAML-Toolkits/ruby-saml/releases/tag/v1.12.4)
- [github.com](https://github.com/SAML-Toolkits/ruby-saml/releases/tag/v1.18.0)
- [portswigger.net](https://portswigger.net/research/saml-roulette-the-hacker-always-wins)
- [securitylab.github.com](https://securitylab.github.com/advisories/GHSL-2024-329_GHSL-2024-330_ruby-saml)
- [security.netapp.com](https://security.netapp.com/advisory/ntap-20250314-0009/)
- [news.ycombinator.com](https://news.ycombinator.com/item?id=43374519)
- [lists.debian.org](https://lists.debian.org/debian-lts-announce/2025/04/msg00011.html)
- [github.com](https://github.com/rubysec/ruby-advisory-db/blob/master/gems/ruby-saml/CVE-2025-25292.yml)

---
Source page: https://erroneo.us/security/cve/CVE-2025-25292/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt