CVE-2026-67339Network attack vectorHinoki check available

Proxy credential disclosure via origin-bound header routing

Published Aug 1, 2026 · Updated Aug 1, 2026

Credential disclosure in Guzzle before 7.14.2 allows remote attackers to obtain proxy credentials via crafted request destinations. The cURL handlers place first-class Proxy-Authorization values in CURLOPT_HTTPHEADER and migrate them only when Guzzle predicts an HTTP proxy. Exposure requires an application-configured first-class proxy credential and a direct, bypassed, SOCKS, or cross-origin redirected route; an attacker-controlled origin can log and reuse the credential.

CVSS severity6.9
Medium
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Credential disclosure in Guzzle before 7.14.2 allows remote attackers to obtain proxy credentials via crafted request destinations. The cURL handlers place first-class Proxy-Authorization values in CURLOPT_HTTPHEADER and migrate them only when Guzzle predicts an HTTP proxy. Exposure requires an application-configured first-class proxy credential and a direct, bypassed, SOCKS, or cross-origin redirected route; an attacker-controlled origin can log and reuse the credential.

The record

CVE
CVE-2026-67339
Published
Aug 1, 2026
Updated
Aug 1, 2026
Vendor
Guzzle
Product
Guzzle
Classifications
CWE-200
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 1, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <7.14.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Guzzle · Guzzleversion=0 <7.14.2

Published CVSS scores

6.9VulnCheck CNACVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
5.3GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-200Exposure of Sensitive Information to an Unauthorized Actor

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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