VulnerabilityPublished 18 May 2026

CVE-2025-65954: simplesamlphp-module-casserver · Open Redirect

Affects simplesamlphp-module-casserverSource CVE Database V5

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Not known to be exploited · CVSS 4.7 Medium : upgrade to 7.0.0 or 6.3.1 when convenient.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.0 base score

4.7Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 19% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 7.0.0, 6.3.1

CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Changed
Confidentiality: None
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 18 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade simplesamlphp-module-casserver to 7.0.0 or 6.3.1; simplesamlphp/simplesamlphp-module-casserver to 6.3.1.

Affected software

Product	Affected	Fixed in
simplesamlphpsimplesamlphp-module-casserver	Affected >=7.0.0-rc1 <7.0.0	Fixed in 7.0.0
simplesamlphpsimplesamlphp-module-casserver	Affected <6.3.1	Fixed in 6.3.1
GitHubsimplesamlphp/simplesamlphp-module-casserver`pkg:github/simplesamlphp/simplesamlphp-module-casserver`Other threats	Affected <6.3.1	Fixed in 6.3.1

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AI-suggested

Upgrade affected installations of simplesamlphp-module-casserver to version 6.3.1 or later, or to version 7.0.0 or later where the issue is fixed. Since this is a module vulnerability and not a cloud service, manual patching by updating the software is required. There is no vendor advisory explicitly stating otherwise, so applying the official fixed versions is the recommended remediation.

Description

SimpleSAMLphp-casserver is a CAS 1.0 and 2.0 compliant CAS server in the form of a SimpleSAMLphp module. In versions below 6.3.1 and 7.0.0, the logout endpoint accepts a url query parameter to redirect to.casserver treats that url as trusted, and either (depending on configuration) redirects the browser there, or shows a "you've been logged out" page with a link to continue to that url. Impacted configs include 'enable_logout' => true, and 'skip_logout_page' -> true. This issue has been resolved in versions 6.3.1 and 7.0.0.

Impact

An attacker can exploit this vulnerability to redirect users to arbitrary, potentially malicious external websites after logout, which may facilitate phishing or social engineering attacks. There is no direct impact on confidentiality or availability, but the integrity of user navigation flow is compromised. The CVSS base score of 4.7 reflects a medium severity with no confidentiality or availability impact but some integrity impact.

Summary

The simplesamlphp-module-casserver, a CAS-compliant server module, contains an open redirect vulnerability (CWE-601) in its logout endpoint. Versions below 6.3.1 and certain 7.0.0 pre-release versions accept a URL parameter for redirection after logout without proper validation, treating the URL as trusted. This can lead to users being redirected to untrusted external sites if the configuration enables logout and skips the logout page. The issue is resolved in versions 6.3.1 and 7.0.0.

CWE-601URL Redirection to Untrusted Site (Open Redirect) (opens in a new tab)
Base weaknessLikelihood of exploit: LowOWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Architecture and Design
Use an intermediate disclaimer page that provides the user with a clear warning that they are leaving the current site. Implement a long timeout before the redirect occurs, or force the user to click on the link. Be careful to avoid XSS problems (CWE-79) when generating the disclaimer page.
Architecture and Design · Enforcement by Conversion
When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs.
OWASP Cheat Sheets
Mass Assignment (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V5.1.5 (opens in a new tab)
Attack patterns
Cross-Site Flashing (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 18 May 2026, 21:06 UTC

WeaknessesCWE-601

Technical details

References

Community reviews

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