Capture-replay flaw in Drupal SAML SSO allows authentication bypass
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- High
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- None · Low · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-294.
Summary
Drupal SAML SSO - Service Provider versions from 0.0.0 before 3.2.0 are affected. Insufficient replay protection lets a captured SAML authentication message be reused (CWE-294). A remote attacker who has stolen credentials can replay captured messages to bypass authentication, though the attack is hard to carry out and requires low privileges.
Written with Claude Haiku 5.5 from the sources below · 2026-10-28
Description from the CNA
Authentication Bypass by Capture-replay vulnerability in Drupal SAML SSO - Service Provider allows Remote Services with Stolen Credentials. This issue affects SAML SSO - Service Provider versions: from 0.0.0 to 3.2.0.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
Upgrade Drupal SAML SSO - Service Provider to version 3.2.0. The fix is listed in Drupal security advisory SA-CONTRIB-2026-150.
Written with Claude Haiku 5.5 from the sources below · 2026-10-28
- Fix · CNA SAML SSO - Service Provider (Drupal) Fixed in 3.2.0
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
Drupal SAML SSO - Service Provider 3.2.0
11 records Highest priority Priority LOW 11 LOW
Other records, highest priority first
- TI-2026-79090 Missing authorization in Drupal SAML SSO - Service Provider modulePriority LOW 34
- TI-2026-79097 Hard-coded credentials in Drupal SAML SSO Service Provider modulePriority LOW 30
- TI-2026-79092 Open redirect in Drupal SAML SSO - Service Provider modulePriority LOW 24
Timeline
- 2026-10-22 Threatist record created from CVE-2026-87952
- 2026-10-22 Alias added: GHSA-899f-rjw2-fh3g
- 2026-10-22 CVSS score added · CISA ADP
- 2026-10-22 CISA SSVC decision points changed
References
More Drupal vulnerabilities
- TI-2026-07979 Drupal core - Highly critical - SQL injection - SA-CORE-2026-004 KEVCVSS 3.1CRITICAL 9.8
- TI-2018-05494 Drupal core - Highly critical - Remote Code Execution - SA-CORE-2018-004 KEVCVSS 3.1CRITICAL 9.8
- TI-2018-05493 Improper input validation in Drupal before 7.58, 8.x before 8.3.9, 8.4.x before 8.4.6… KEVCVSS 3.1CRITICAL 9.8
- TI-2020-10731 Unrestricted file upload in Drupal Core KEVCVSS 3.1HIGH 8.8
- TI-2019-04505 Drupal core - Highly critical - Remote Code Execution KEVCVSS 3.1HIGH 8.1
- TI-2020-17477 Archive_Tar through 1.4.10 has :// filename sanitization only to address phar attacks… KEVCVSS 3.1HIGH 7.8
Sources
- CVE-2026-87952 · CVE Program
- CVE-2026-87952 · NVD
- FIRST EPSS
- GHSA-899f-rjw2-fh3g · GitHub Advisory Database · CC BY 4.0
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