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FirefoxWeb browser · Mozilla

CVE-2009-0357

MEDIUM · 5.0 CVSS v2.0 Published 2009-02-04
Fix available
A fix is available. Upgrade to after 3.0.5 or later.
See remediation →
59/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

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
Mozilla Firefox before 3.0.6 and SeaMonkey before 1.1.15 do not properly restrict access from web pages to the (1) Set-Cookie and (2) Set-Cookie2 HTTP response headers, which allows remote attackers to obtain sensitive information from cookies via XMLHttpRequest calls, related to the HTTPOnly protection mechanism.

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

Firefox before 3.0.6 and SeaMonkey before 1.1.15 fail to properly restrict access to Set-Cookie and Set-Cookie2 HTTP response headers, allowing malicious web pages to use XMLHttpRequest to read cookie values and bypass HTTPOnly protection mechanisms.

MitigationUpgrade affected browsers to Firefox 3.0.6+ or SeaMonkey 1.1.15+ to restore proper HTTPOnly cookie protection.

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
Affected:<= 3.0.5= 0.1= 0.2= 0.3= 0.4= 0.5= 0.6= 0.6.1= 0.7= 0.7.1= 0.8= 0.9
SeamonkeyApplication
Affected:<= 1.1.13= 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

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
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 checks

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

  1. Identify installed Firefox version
    In Firefox, go to Help > About Firefox (or navigate to about:support). Record the version number displayed.
    Affected if The version is 3.0.5 or earlier, or falls within 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.6.1, 0.7, 0.7.1, 0.8, or 0.9.
  2. Identify installed SeaMonkey version
    In SeaMonkey, go to Help > About SeaMonkey. Record the version number displayed.
    Affected if The version is 1.1.13 or earlier, or falls within 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, or 1.1.
  3. Confirm XMLHttpRequest is available
    XMLHttpRequest is enabled by default in both Firefox and SeaMonkey. This check is satisfied if the browser can load web pages normally.
    Affected if This vulnerability is exploitable in any standard browser installation where XMLHttpRequest is functional, which is the default state.

You are affected if you run Firefox 3.0.5 or earlier (including 0.x series) or SeaMonkey 1.1.13 or earlier (including 1.0.x and 1.1), as these versions allow XMLHttpRequest to read Set-Cookie headers and bypass HTTPOnly protection.

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.

From vendor data
Upgrade available Upgrade to a release after 3.0.5
Interim mitigation

Upgrade affected browsers to Firefox 3.0.6+ or SeaMonkey 1.1.15+ to restore proper HTTPOnly cookie protection.

Fix this in Firefox Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing1.0 h
  • Review / QA1.0 h
4.0 hours of engineering $750
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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-2009-0357 in production — separate from our analysis above.

No notes yet

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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