CVE-2026-87937
Central Authentication System (CAS) Server - Moderately critical - Open redirect - SA-CONTRIB-2026-135
URL Redirection to Untrusted Site ('Open Redirect') vulnerability in Drupal Central Authentication System (CAS) Server allows Fake the Source of Data. This issue affects Central Authentication System (CAS) Server versions: from 0.0.0 to 2.0.4, from 2.1.0 to 2.1.3.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Central Authentication System (CAS) Server - Moderately critical - Open redirect - SA-CONTRIB-2026-135
URL Redirection to Untrusted Site ('Open Redirect') vulnerability in Drupal Central Authentication System (CAS) Server allows Fake the Source of Data. This issue affects Central Authentication System (CAS) Server versions: from 0.0.0 to 2.0.4, from 2.1.0 to 2.1.3.
- Record
CVE-2026-87937- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N - Weakness
- CWE-601
- Updated
- 2026-11-02
EUVDEUVD-2026-107864
URL Redirection to Untrusted Site ('Open Redirect') vulnerability in Drupal Central Authentication System (CAS) Server allows Fake the Source of Data. This issue affects Central Authentication System (CAS) Server versions: from 0.0.0 to 2.0.4, from 2.1.0 to 2.1.3.
- Record
EUVD-2026-107864- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-9m9j-x6cp-vc3f
URL Redirection to Untrusted Site ('Open Redirect') vulnerability in Drupal Central...
URL Redirection to Untrusted Site ('Open Redirect') vulnerability in Drupal Central Authentication System (CAS) Server allows Fake the Source of Data. This issue affects Central Authentication System (CAS) Server versions: from 0.0.0 to 2.0.4, from 2.1.0 to 2.1.3.
- Record
GHSA-9m9j-x6cp-vc3f- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N - Weakness
- CWE-601
- Updated
- 2026-11-02
NVD
URL Redirection to Untrusted Site ('Open Redirect') vulnerability in Drupal Central Authentication System (CAS) Server allows Fake the Source of Data. This issue affects Central Authentication System (CAS) Server versions: from 0.0.0 to 2.0.4, from 2.1.0 to 2.1.3.
- Record
CVE-2026-87937- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N - Weakness
- CWE-601
- Updated
- 2026-11-02
OSV
Central Authentication System (CAS) Server - Moderately critical - Open redirect - SA-CONTRIB-2026-135
URL Redirection to Untrusted Site ('Open Redirect') vulnerability in Drupal Central Authentication System (CAS) Server allows Fake the Source of Data. This issue affects Central Authentication System (CAS) Server versions: from 0.0.0 to 2.0.4, from 2.1.0 to 2.1.3.
- Record
CVE-2026-87937- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N - Weakness
- CWE-601
- Updated
- 2026-11-02
OSVDRUPAL-CONTRIB-2026-135 No score
This module enables you to turn a Drupal install into the Central Authentication System (CAS) Server. It makes your database the primary location for other systems to use for authentication in a SSO environment.
The module doesn't sufficiently check the service URL used to redirect the user during logout, leading to an open redirect.
This vulnerability is mitigated by the fact that an attacker must convince a user to click a specially crafted link. The vulnerability cannot be exploited without user interaction and does not allow an attacker to directly compromise the CAS server or bypass authentication.
- Record
DRUPAL-CONTRIB-2026-135- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
drupal/cas_serverPackagist:https://packages.drupal.org/8 |
before 2.0.4, 2.1.0 up to 2.1.3 | 2.0.42.1.3 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-87937 is a medium vulnerability (CVSS 6.5) in Drupal Central Authentication System (cas) Server, published September 9, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.28%, the 21st percentile. Fixed in drupal/cas_server 2.0.4.