SymfonyFramework / library · Sensiolabs
CVE-2018-11406
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 · uneditedAn issue was discovered in the Security component in Symfony 2.7.x before 2.7.48, 2.8.x before 2.8.41, 3.3.x before 3.3.17, 3.4.x before 3.4.11, and 4.0.x before 4.0.11. By default, a user's session is invalidated when the user is logged out. This behavior can be disabled through the invalidate_session option. In this case, CSRF tokens were not erased during logout which allowed for CSRF token fixation.
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 confidenceIn Symfony's Security component, when the `invalidate_session` option is set to false during logout configuration, CSRF tokens are not cleared from the session. This allows an attacker to perform CSRF token fixation attacks by potentially fixing or reusing tokens across user sessions, bypassing CSRF protections.
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
>= 2.7.0, < 2.7.48>= 2.8.0, < 2.8.41>= 3.3.0, < 3.3.17>= 3.4.0, < 3.4.11>= 4.0.0, < 4.0.11
Debian LinuxOperating system
= 9.0CVSS 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
- High
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
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 checksWork through these to decide whether this CVE applies to you.
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Check Symfony framework versionInspect the file `vendor/symfony/symfony/composer.json` or run `composer show symfony/symfony | grep version` to identify the installed Symfony version.Affected if The installed version falls within any of these ranges: >= 2.7.0 and < 2.7.48; >= 2.8.0 and < 2.8.41; >= 3.3.0 and < 3.3.17; >= 3.4.0 and < 3.4.11; >= 4.0.0 and < 4.0.11
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Locate security firewall logout configurationOpen the security configuration file (typically `app/config/security.yml` for older Symfony or `config/packages/security.yaml` for Symfony 4) and locate the `logout` section under your firewall.Affected if A logout configuration section exists in the security firewall settings.
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Verify invalidate_session settingWithin the logout configuration, look for the `invalidate_session` option and confirm its value.Affected if The `invalidate_session` option is explicitly set to `false`.
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Confirm CSRF token handling during logoutReview the logout handler code in your project or the Symfony Security component to verify whether CSRF tokens are explicitly cleared from the session upon logout.Affected if CSRF tokens are not removed from the session when logout occurs, particularly when session invalidation is disabled.
You are affected if you are running a Symfony version within the affected ranges listed and your logout configuration sets `invalidate_session` to false without explicitly clearing CSRF tokens.
Generated from the published advisory. Verify against your own configuration.
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.
From vendor data2.7.482.8.413.3.17
Upgrade Symfony to version 2.7.48, 2.8.41, 3.3.17, 3.4.11, or 4.0.11 or later, which properly invalidates CSRF tokens during logout regardless of session invalidation settings.
Fix this in Symfony
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-11406 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2018-11406 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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