Medium severity · published Jul 8, 2026
CVE-2026-59882
guzzlehttp/psr7: Host Confusion via Weak URI Host Validation
6.5
CVSS
0.3%
EPSS
No
On KEV
Description
guzzlehttp/psr7 is a PSR-7 HTTP message library implementation in PHP. Prior to 2.12.3, Uri::assertValidHost() does not reject URI host components containing authority delimiters, embedded ports, or malformed IPv6 brackets, allowing Uri::getHost() to disagree with the URI authority used for security or routing decisions. This issue is fixed in version 2.12.3.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 25% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
PS
psr7 · guzzle
< 2.12.3 · source: vendor
PS
Psr-7 · Guzzlephp
before 2.12.3 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-59882
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-59882
Patch
https://github.com/guzzle/psr7/commit/ddd64f17d4cc1f7e5ffe6fd2c989ec7221712580
Issue Tracking
https://github.com/guzzle/psr7/pull/811
Product
https://github.com/guzzle/psr7/releases/tag/2.12.3
Mitigation
https://github.com/guzzle/psr7/security/advisories/GHSA-c2w2-prh8-qm98
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