CVE-2026-95806

MISP: PHP phar stream wrapper enables deserialization and code execution via caller-influenced filesystem paths

Published Sep 22, 2026 CVSS 4.0 · 7.7 High EPSS < 1% KEV · Not listed
Description
MISP ships with PHP's phar stream wrapper registered in both its web entry point and its console entry point. 

The phar stream wrapper causes PHP to treat a phar archive as a directory, which has two security consequences:  

 - any filesystem operation on a caller-influenced path that resolves to a phar archive triggers an implicit unserialize() call, creating a deserialization sink;
 - a relocated application root can reach executable code inside an uploaded phar file, enabling arbitrary code execution as the web user.




No component of MISP, the vendored CakePHP framework, or any runtime-loaded library reads or constructs phar archives. The wrapper therefore serves no legitimate purpose in the MISP runtime and exists solely as an available primitive for an attacker who can influence a filesystem path argument.

Remediation

Vendor Solution

The phar stream wrapper is unregistered via stream_wrapper_unregister('phar') at the top of both the web and console entry points, before any framework bootstrap or application code executes. Because no MISP component, CakePHP, or runtime library requires the phar wrapper, removing it eliminates the implicit unserialize() sink and the directory-like phar archive behavior without functional impact. This closes the deserialization and code-execution primitive application-wide, independent of whether individual callers validate their path arguments.

Tracking

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Advisories

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History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Misp
Misp misp
Vendors & Products Misp
Misp misp
Type Values Removed Values Added
Description MISP ships with PHP's phar stream wrapper registered in both its web entry point and its console entry point.  The phar stream wrapper causes PHP to treat a phar archive as a directory, which has two security consequences:    - any filesystem operation on a caller-influenced path that resolves to a phar archive triggers an implicit unserialize() call, creating a deserialization sink;  - a relocated application root can reach executable code inside an uploaded phar file, enabling arbitrary code execution as the web user. No component of MISP, the vendored CakePHP framework, or any runtime-loaded library reads or constructs phar archives. The wrapper therefore serves no legitimate purpose in the MISP runtime and exists solely as an available primitive for an attacker who can influence a filesystem path argument.
Title MISP: PHP phar stream wrapper enables deserialization and code execution via caller-influenced filesystem paths
Weaknesses CWE-502
CWE-74
References
Metrics cvssV4_0

{'score': 7.7, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
CIRCL
Published
Updated
Sep 22, 2026, 3:54 PM
Reserved
Sep 22, 2026, 3:09 PM
Status
Deferred
Published
Sep 22, 2026, 4:18 PM
Modified
Sep 22, 2026, 4:18 PM