5.3

CVSS Score

3.1

-

CVSS Score

Basic Information

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CVE-2025-26803

CVE-2025-26803: Phusion Passenger denial of service

The http parser in Phusion Passenger 6.0.21 through 6.0.25 before 6.0.26 allows a denial of service during parsing of a request with an invalid HTTP method.

(GitHub Advisory)

Miggo Vulnerability Database

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CVE-2025-26803

CVE-2025-26803:

5.3

CVSS Score

3.1

-

CVSS Score

Basic Information

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Technical Details

Package Name	Ecosystem	Vulnerable Versions	First Patched Version
passenger	rubygems	>= 6.0.21, < 6.0.26	6.0.26

Technical Details

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Root Cause Analysis

The vulnerability stems from the HTTP header parser's error handling logic. The commit diff shows critical modifications to http_parser_execute_and_handle_pause() where:

The 'paused' output parameter was removed
Error code handling was restructured
Post-execution state validation was added
A new test case for invalid HTTP methods was introduced

These changes indicate the original implementation failed to properly handle parser resumption states and error propagation when encountering malformed requests. The CWE-908 mapping suggests uninitialized parser states could be exploited to cause a DoS. The direct correlation between the patched function and the vulnerability description, combined with the added test case validating HTTP method handling, provides high confidence in this identification.

Vulnerable functions

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WAF Protection Rules

WAF Rule

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Reasoning

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