FirefoxWeb browser · Mozilla
CVE-2011-2990
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 · uneditedThe implementation of Content Security Policy (CSP) violation reports in Mozilla Firefox 4.x through 5, SeaMonkey 2.x before 2.3, and possibly other products does not remove proxy-authorization credentials from the listed request headers, which allows attackers to obtain sensitive information by reading a report, related to incorrect host resolution that occurs with certain redirects.
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 confidenceMozilla Firefox 4.x-5 and SeaMonkey 2.x before 2.3 contain a flaw in Content Security Policy violation report generation. When CSP violations occur with certain redirects, proxy-authorization credentials are not removed from request headers listed in the violation report, allowing attackers to read sensitive proxy credentials from the report.
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
FirefoxWeb browser
= 4.0= 4.0.1= 5.0= 1.0= 1.0.1= 1.0.2= 1.0.3= 1.0.4= 1.0.5= 1.0.6= 1.0.7= 1.0.8= 1.0.9= 1.1= 1.1.1CVSS 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
- Authentication
- None
- Confidentiality
- Partial
- Integrity
- None
- Availability
- None
AV:N/AC:L/Au:N/C:P/I:N/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 checksWork through these to decide whether this CVE applies to you.
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Identify installed Firefox versionIn Firefox, go to Help > About Firefox (or navigate to about:support). Record the version number displayed.Affected if The version is 4.0, 4.0.1, or 5.0 (or any 4.x version up to 5.0 not explicitly listed but within the 4.x-5 range).
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Identify installed SeaMonkey versionIn SeaMonkey, go to Help > About SeaMonkey. Record the version number displayed.Affected if The version is 1.0.x (any 1.0.x), 1.1, 1.1.1, or any 2.x version prior to 2.3.
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Confirm Content Security Policy is in useInspect web application configurations or check if the browser is configured to enforce CSP headers. Look for CSP policy headers (Content-Security-Policy) being sent by websites or check browser CSP settings in about:config for 'content.policy' entries.Affected if CSP policies are actively enforced or configured in the browser environment.
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Verify proxy authentication is configuredCheck browser proxy settings: go to Firefox/SeaMonkey Preferences > Advanced > Network > Settings, or inspect system proxy configuration. Look for authenticated proxy connections (proxy servers requiring username/password).Affected if A proxy server requiring authentication (proxy-authorization credentials) is configured and active.
A user is affected if they run Firefox 4.0-5.0 or SeaMonkey 1.0-2.x (pre-2.3), have Content Security Policy enabled, and use proxy authentication simultaneously.
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 dataUpdate affected Mozilla products to patched versions (Firefox 6+ or SeaMonkey 2.3+). Until patched, avoid using proxy authentication with CSP-protected sites.
Fix this in Firefox
Scoped from the published advisory
- Consultation1.0 h
- Implementation2.0 h
- Testing1.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,424.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2011-2990 — 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-2011-2990 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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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.
- 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
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