Medium 4.2Published Jul 8, 2026

CVE-2026-59882guzzlehttp/psr7: Host Confusion via Weak URI Host Validation

Updated under an hour ago (Oct 27, 2026, 12:10 PM ET)

Does this affect you?

It affects guzzle psr7 and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Do this next

Start free and add your stack

Free account, 1 product

Every CVE for guzzle psr7

Exploited in the last 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.

CVSS: 4.2 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
Weakness (CWE): CWE-436
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Jul 8, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

guzzle psr7 guzzle:psr7 (from the name)	before 2.12.3	CNA record
guzzlephp psr-7 guzzlephp:psr-7	before 2.12.3	NVD

References

References

https://github.com/guzzle/psr7/security/advisories/GHSA-c2w2-prh8-qm98	x-refsource-confirm, mitigation, vendor-advisory
https://github.com/guzzle/psr7/pull/811	x-refsource-misc, issue-tracking, patch
https://github.com/guzzle/psr7/commit/ddd64f17d4cc1f7e5ffe6fd2c989ec7221712580	x-refsource-misc, patch
https://github.com/guzzle/psr7/releases/tag/2.12.3	x-refsource-misc, product, release-notes

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.