CVE-2026-67355Network attack vectorHinoki check available

Cookie disclosure via lost host-only scope

Published Aug 1, 2026 · Updated Aug 1, 2026

Information disclosure in Guzzle before 7.15.1 allows remote attackers controlling child hosts to receive parent-host cookies. CookieJar replaces an absent or empty Domain attribute with the request host, then applies ordinary domain matching instead of recording host-only state. Exploitation requires enabled cookie support, one built-in jar reused across trust boundaries, and a later request to a less-trusted child host; exposed cookies can include session identifiers or authorization tokens.

CVSS severity8.2
High
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Information disclosure in Guzzle before 7.15.1 allows remote attackers controlling child hosts to receive parent-host cookies. CookieJar replaces an absent or empty Domain attribute with the request host, then applies ordinary domain matching instead of recording host-only state. Exploitation requires enabled cookie support, one built-in jar reused across trust boundaries, and a later request to a less-trusted child host; exposed cookies can include session identifiers or authorization tokens.

The record

CVE
CVE-2026-67355
Published
Aug 1, 2026
Updated
Aug 1, 2026
Vendor
Guzzle
Product
Guzzle
Classifications
CWE-941, CWE-201, T1539
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 <7.15.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Guzzle · Guzzleversion=0 <7.15.1

Published CVSS scores

8.2VulnCheckCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
5.9GitHub Security AdvisoryCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-941Incorrectly Specified Destination in a Communication Channel
CWE-201Insertion of Sensitive Information Into Sent Data
T1539Steal Web Session Cookie

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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