CVE-2026-59882: CWE-436: Interpretation Conflict in guzzle psr7
A vulnerability in guzzlehttp/psr7 prior to version 2.12.3 allows the Uri::assertValidHost() function to accept URI host components with authority delimiters, embedded ports, or malformed IPv6 brackets. This causes Uri::getHost() to produce a different host value than the URI authority used in security or routing decisions. The issue is fixed in version 2.12.3.
AI Analysis
Technical Summary
The guzzlehttp/psr7 PHP library, which implements PSR-7 HTTP message interfaces, contains an interpretation conflict vulnerability (CWE-436) in versions before 2.12.3. The Uri::assertValidHost() method does not properly reject invalid URI host components that include authority delimiters, embedded ports, or malformed IPv6 brackets. This discrepancy allows Uri::getHost() to return a host value that differs from the URI authority component used in security or routing logic, potentially leading to incorrect access control or routing decisions. The vulnerability is addressed in version 2.12.3 by correcting the validation logic.
Potential Impact
This vulnerability can cause security or routing decisions based on the URI host to be inconsistent, potentially allowing bypasses or misrouting due to differing interpretations of the host component. The CVSS score of 4.2 (medium) reflects limited confidentiality and integrity impact with no availability impact. There are no known exploits in the wild.
Mitigation Recommendations
Upgrade guzzlehttp/psr7 to version 2.12.3 or later, where the issue is fixed. No other mitigation or temporary workaround is indicated. Patch status is not explicitly stated as 'official-fix' in the vendor advisory, but the description confirms the fix in 2.12.3.
CVE-2026-59882: CWE-436: Interpretation Conflict in guzzle psr7
Description
A vulnerability in guzzlehttp/psr7 prior to version 2.12.3 allows the Uri::assertValidHost() function to accept URI host components with authority delimiters, embedded ports, or malformed IPv6 brackets. This causes Uri::getHost() to produce a different host value than the URI authority used in security or routing decisions. The issue is fixed in version 2.12.3.
CVSS v3.1
Score 4.2medium
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The guzzlehttp/psr7 PHP library, which implements PSR-7 HTTP message interfaces, contains an interpretation conflict vulnerability (CWE-436) in versions before 2.12.3. The Uri::assertValidHost() method does not properly reject invalid URI host components that include authority delimiters, embedded ports, or malformed IPv6 brackets. This discrepancy allows Uri::getHost() to return a host value that differs from the URI authority component used in security or routing logic, potentially leading to incorrect access control or routing decisions. The vulnerability is addressed in version 2.12.3 by correcting the validation logic.
Potential Impact
This vulnerability can cause security or routing decisions based on the URI host to be inconsistent, potentially allowing bypasses or misrouting due to differing interpretations of the host component. The CVSS score of 4.2 (medium) reflects limited confidentiality and integrity impact with no availability impact. There are no known exploits in the wild.
Mitigation Recommendations
Upgrade guzzlehttp/psr7 to version 2.12.3 or later, where the issue is fixed. No other mitigation or temporary workaround is indicated. Patch status is not explicitly stated as 'official-fix' in the vendor advisory, but the description confirms the fix in 2.12.3.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-07-07T16:40:07.982Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a4e7ad4c9d9e3dbe36a7d5d
Added to database: 07/08/2026, 16:29:08 UTC
Last enriched: 07/22/2026, 00:58:00 UTC
Last updated: 08/22/2026, 10:52:10 UTC
Views: 77
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