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SymfonyFramework / library · Sensiolabs

CVE-2026-45074

HIGH · 8.1 CVSS v3.1 Published 2026-07-14
Fix available
A fix is available. Upgrade to 7.4.12 / 8.0.12 or later.
See remediation →
88/100
Remediation priority · High
Remotely reachable No privileges 5 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 7.1.0 until 7.4.12 and 8.0.12, Cas2Handler builds the CAS service parameter from Request::getSchemeAndHttpHost(), which reflects an attacker-controlled Host header when framework.trusted_hosts is not configured; an attacker controlling another application registered with the same CAS server can replay a victim ticket against the Symfony application and authenticate as the victim. This issue is fixed in versions 7.4.12 and 8.0.12.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The Cas2Handler in Symfony builds the CAS service parameter using Request::getSchemeAndHttpHost(), which reflects the attacker-controlled Host header when framework.trusted_hosts is not configured. This allows an attacker to manipulate the CAS service URL and replay stolen victim tickets to authenticate as the victim user.

MitigationConfigure framework.trusted_hosts to explicitly list allowed hostnames and update Symfony to version 7.4.12 or 8.0.12 to receive the fix.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
SymfonyFramework / library
Affected:>= 7.1.0, < 7.4.12>= 8.0.0, < 8.0.12

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed Symfony version
    Run `composer show symfony/symfony` or check your composer.lock file for the symfony/symfony package version
    Affected if Version is >= 7.1.0 and < 7.4.12, or >= 8.0.0 and < 8.0.12
  2. Confirm CAS2Handler is in use
    Search your codebase for references to Cas2Handler, cas, or CAS authentication in your security configuration files (e.g., security.yaml, security.php)
    Affected if Your application uses CAS2 authentication via the Cas2Handler class
  3. Inspect trusted_hosts configuration
    Check your Symfony framework configuration (config/packages/framework.yaml or equivalent) for the framework.trusted_hosts setting
    Affected if framework.trusted_hosts is not set, is empty, or does not explicitly list your application's allowed hostnames
  4. Verify Host header handling
    Review your application code to confirm it uses Request::getSchemeAndHttpHost() for building CAS service URLs without validating against trusted_hosts
    Affected if The CAS service URL is constructed using the Host header without explicit whitelist validation

Your environment is affected if you run a vulnerable Symfony version (7.1.0 to 7.4.11 or 8.0.0 to 8.0.11), use CAS2 authentication, and have not configured framework.trusted_hosts to restrict allowed hostnames.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 7.4.12 / 8.0.12 or later
Fixed in 7.4.128.0.12
Interim mitigation

Configure framework.trusted_hosts to explicitly list allowed hostnames and update Symfony to version 7.4.12 or 8.0.12 to receive the fix.

Recommended fix High confidence

Symfony 7.4.12+ or 8.0.12+

  1. Upgrade Symfony to version 7.4.12 or later for the 7.x branch
  2. Upgrade Symfony to version 8.0.12 or later for the 8.x branch
  3. After upgrading, verify that the Cas2Handler now properly validates the host before building the CAS service parameter
  4. As an additional safeguard, configure framework.trusted_hosts in config/packages/framework.yaml to explicitly list allowed hostnames
Caveat Minor version upgrades within same major should have minimal breaking changes; review Symfony's changelog for any deprecation notices

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Symfony Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,408.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-45074 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data