CVE-2026-59882: Guzzlephp Psr-7

Medium severity, CVSS 6.5. EPSS: 0.3% chance of exploitation in the next 30 days.

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.

Affected products

• Guzzlephp Psr-7: before 2.12.3 (fixed in 2.12.3)

Published 2026-07-08. Last modified 2026-07-17.