CVE-2026-55806Network attack vector

Cache poisoning and redirects via unchecked Host header

Published Jul 10, 2026 · Updated Jul 10, 2026

Open redirect in Drupal core before 10.5.12 and affected 10.6 and 11 releases allows remote attackers to redirect users via rebuild.php. The front controller fails to compare the untrusted Host header with configured trusted host patterns before using it in rebuild responses and cache state. Exploitation requires access to rebuild.php and a crafted Host header, and it can poison caches or send users to an attacker-controlled domain.

CVSS severity5.9
Medium
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Open redirect in Drupal core before 10.5.12 and affected 10.6 and 11 releases allows remote attackers to redirect users via rebuild.php. The front controller fails to compare the untrusted Host header with configured trusted host patterns before using it in rebuild responses and cache state. Exploitation requires access to rebuild.php and a crafted Host header, and it can poison caches or send users to an attacker-controlled domain.

The record

CVE
CVE-2026-55806
Published
Jul 10, 2026
Updated
Jul 10, 2026
Vendor
Avatar Uploader Project
Product
Drupal core
Classifications
CWE-601, CAPEC-148, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 10, 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=0.0.0 <10.5.12
  2. Affected versionversion=0.0.0 <11.0.*
  3. Affected versionversion=0.0.0 <11.1.*
  4. Affected versionversion=10.6.0 <10.6.11
  5. Affected versionversion=11.2.0 <11.2.14
  6. Affected versionversion=11.3.0 <11.3.12

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Avatar Uploader Project · Drupal coreversion=0.0.0 <10.5.12; version=0.0.0 <11.0.*; version=0.0.0 <11.1.*; version=10.6.0 <10.6.11; version=11.2.0 <11.2.14; version=11.3.0 <11.3.12

Published CVSS scores

5.9CISA-ADPCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-601URL Redirection to Untrusted Site ('Open Redirect')
CAPEC-148Content Spoofing
T1190Exploit Public-Facing Application

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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