vulnerability / NVI-00005306 / Revision 3
Guzzle: Host-only cookie scope is not preserved
GitHub lists this reviewed advisory for guzzlehttp/guzzle. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
5.9 medium
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
0.366%
FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.30517. Missing scores are unknown.
As of · FIRST EPSS
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
guzzlehttp/guzzle
source listed< 7.15.1
### Impact In affected versions, `CookieJar` does not preserve whether a response cookie was set without a `Domain` attribute or with an empty one. A cookie without `Domain` is host-only and must be returned only to the exact host that set it. Under current cookie processing rules, an empty `Domain` value is also host-only. Guzzle instead stores the request host in the cookie's `Domain` field and later applies ordinary domain matching, as though the server had supplied a valid domain. For example, a host-only `sid=secret` cookie set by `example.com` can subsequently be sent to `child.example.com`. `FileCookieJar` and `SessionCookieJar` also persist the request host without recording the host-only state, so reloading a jar preserves the widened scope. An attacker who controls or can observe a child host can therefore receive cookies that were intended only for its parent host. Depending on the cookie, this can disclose session identifiers, authorization tokens, or other sensitive state. Exploitation requires the application to enable Guzzle's cookie support, reuse the same built-in cookie jar, receive a host-only cookie from a parent host, and later make a matching request to a le
guzzlehttp/guzzle
source listedECOSYSTEM: introduced 0; fixed 7.15.1
### Impact In affected versions, `CookieJar` does not preserve whether a response cookie was set without a `Domain` attribute or with an empty one. A cookie without `Domain` is host-only and must be returned only to the exact host that set it. Under current cookie processing rules, an empty `Domain` value is also host-only. Guzzle instead stores the request host in the cookie's `Domain` field and later applies ordinary domain matching, as though the server had supplied a valid domain. For example, a host-only `sid=secret` cookie set by `example.com` can subsequently be sent to `child.example.com`. `FileCookieJar` and `SessionCookieJar` also persist the request host without recording the host-only state, so reloading a jar preserves the widened scope. An attacker who controls or can observe a child host can therefore receive cookies that were intended only for its parent host. Depending on the cookie, this can disclose session identifiers, authorization tokens, or other sensitive state. Exploitation requires the application to enable Guzzle's cookie support, reuse the same built-in cookie jar, receive a host-only cookie from a parent host, and later make a matching request to a le
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. FIRST EPSS
- vendor patch
The original advisory lists fixed boundaries 7.15.1 for guzzlehttp/guzzle. Confirm the publisher’s latest guidance.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database via OSV
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-wm3w-8rrp-j577 ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- GHSA-wm3w-8rrp-j577 ↗
GitHub Advisory Database via OSV · vendor advisory
Observed . GitHub-origin advisory, CC-BY-4.0; OSV is an aggregate copy, not independent corroboration.
- CVE-2026-67355 ↗
FIRST EPSS · official catalog
Observed . FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 3 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 2 ·
Source facts changed; compare the preserved prior revision.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.