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Fencer Vulns
high 7.2

CVE-2026-69246 json

Guzzle: Noncanonical host can bypass host-based checks

published 2026-08-03 3 mo ago modified 2026-09-10 1 mo ago also GHSA-v5mv-p594-2x33 , EUVD-2026-52445

cvss
7.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits
0
none known

Summary

Guzzle is an extensible PHP HTTP client. Prior to 7.15.2 and 8.0.1, Guzzle gives a transport the request URI as text and supplies the Host header separately. The cURL handlers set CURLOPT_URL to the URI exactly as written and push that Host into CURLOPT_HTTPHEADER; StreamHandler does the same through fopen(). libcurl then parses the authority itself, percent-decoding it and, on an IDN-capable build, applying IDNA mapping, and uses the result to resolve, connect, name the TLS peer and address a proxy CONNECT, while the supplied Host suppresses the aligned one libcurl would have generated. For a URI host written as 127.0.0.%31, filter_var() rejects the host as an IP literal, yet libcurl decodes it to 127.0.0.1 and reaches loopback with no DNS lookup while the server receives Host: 127.0.0.%31. An attacker who influences a fetched URI can therefore reach a host the application's checks excluded and read whatever the host exposes of the response. The same divergence moves Guzzle's own decisions onto a spelling the transport does not use: no_proxy selects proxy routing from the literal host, and RedirectMiddleware decides from it whether to strip Authorization and Cookie. Exploitation requires the application to build a request URI from untrusted input and to make a host decision before handing it to Guzzle. This issue is fixed in versions 7.15.2 and 8.0.1.

Patch / fix

  • packagist guzzlehttp/guzzle 7.15.2, 8.0.1
  • guzzle Debian 14 7.15.2-1

debian advisories DEBIAN-CVE-2026-69246

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
GitHub 3.1 7.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
packagist guzzlehttp/guzzle
<7.15.2
>=8.0.0, <8.0.1
7.15.2
8.0.1

Affected products

  • guzzle guzzle

Classification

Weakness
  • CWE-180 Incorrect Behavior Order: Validate Before Canonicalize
  • CWE-436 Interpretation Conflict
  • CWE-918 Server-Side Request Forgery
  • CWE-941 Incorrectly Specified Destination in a Communication Channel

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.