SimpleSAMLphp casserver FileSystemTicketStore path traversal allows out-of-ticket-directory read/unserialize and conditional deletion

published 2026-05-15 5 mo ago modified 2026-09-10 1 mo ago also GHSA-jrrg-99xh-5j2q , EUVD-2026-35871

cvss: 8.6; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 36%
public exploits: 0; none known

SimpleSAMLphp-casserver is a CAS 1.0 and 2.0 compliant CAS server in the form of a SimpleSAMLphp module. Prior to version 7.0.3, simplesamlphp-module-casserver builds file paths for the file-based CAS ticket store by directly concatenating the configured ticket directory with an attacker-controlled ticket identifier. Public CAS validation/proxy endpoints pass attacker-controlled ticket / pgt query parameters into this store. In deployments using FileSystemTicketStore, a remote attacker can use path traversal sequences such as ../target.serialized to make the CAS server read and unserialize files outside the ticket directory. In the CAS 1.0 validation flow, the same attacker-selected path is also passed to deleteTicket() immediately after getTicket() returns, which can delete the target file when it is readable by the PHP process, deletable under the PHP process filesystem permissions, and unserializes to a value compatible with the ?array return type. This issue has been patched in version 7.0.3.

Patch / fix

fixed in 1 links 2

packagist simplesamlphp/simplesamlphp-module-casserver 7.0.3

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: 4 mo ago (2026-06-10)

Exploit prediction

0.42% chance of exploitation in the next 30 days, higher than 36% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	8.6	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L
GitHub	3.1	8.6	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L

Affected packages

ecosystem	package	affected	fixed in
packagist	simplesamlphp/simplesamlphp-module-casserver	<7.0.3	7.0.3

Affected products

simplesamlphp simplesamlphp-module-casserver

Classification

Weakness

CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary