Vulnerability · Published Aug 1, 2026 · Assigned by VulnCheck

CVE-2026-67339guzzlehttp/guzzle before 7.14.2 Proxy-Authorization Header Disclosure

Medium 5.3

In plain English

A medium-severity information exposure in guzzle from guzzle. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 31% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.3Medium

Exploit odds (30 days)0.4%top 68.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

guzzlehttp/guzzle versions before 7.14.2 fail to properly isolate Proxy-Authorization headers from origin servers in cURL handlers. Attackers can capture proxy credentials through origin server access logs when requests are redirected, bypassed, or sent through SOCKS proxies that Guzzle misclassifies as direct connections.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	guzzle	no fix listed	DEBIAN-CVE-2026-67339
Debian:13	guzzle	no fix listed	DEBIAN-CVE-2026-67339
Debian:14	guzzle	7.14.2-1	DEBIAN-CVE-2026-67339
Packagist	guzzlehttp/guzzle	7.14.2	GHSA-94pj-82f3-465w
Ubuntu:24.04:LTS	guzzle	no fix listed	UBUNTU-CVE-2026-67339
Ubuntu:26.04:LTS	guzzle	no fix listed	UBUNTU-CVE-2026-67339
Ubuntu:26.10	guzzle	no fix listed	UBUNTU-CVE-2026-67339

Affected products (as reported)

Vendor	Product	Versions
guzzle	guzzle	0 – before 7.14.2

Weakness: CWE-200 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

References

GitHub Security Advisory (GHSA-94pj-82f3-465w) vendor-advisory
VulnCheck Advisory: guzzlehttp/guzzle before 7.14.2 Proxy-Authorization Header Disclosure third-party-advisory