Enterprise LinuxOperating system · Redhat
CVE-2017-5449
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 · uneditedA possibly exploitable crash triggered during layout and manipulation of bidirectional unicode text in concert with CSS animations. This vulnerability affects Thunderbird < 52.1, Firefox ESR < 52.1, and Firefox < 53.
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 confidenceA memory corruption crash occurs in the layout engine when processing bidirectional Unicode text (e.g., Arabic or Hebrew) combined with CSS animations. The interaction between the bidirectional text reordering algorithm and animated CSS properties causes a possibly exploitable crash.
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
Enterprise LinuxOperating system
= 6.0= 7.0
Enterprise Linux DesktopOperating system
= 6.0= 7.0
Enterprise Linux ServerOperating system
= 6.0= 7.0
Enterprise Linux Server AusOperating system
= 7.3= 7.4
Enterprise Linux Server EusOperating system
= 7.3= 7.4= 7.5
Enterprise Linux WorkstationOperating system
= 6.0= 7.0
FirefoxWeb browser
< 52.1.0< 53.0< 52.1.0CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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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Identify installed Firefox versionRun 'firefox --version' or check the package manager (e.g., 'rpm -q firefox' on RHEL)Affected if Version is earlier than 52.1.0 or falls between 52.1.0 and 53.0 (non-inclusive)
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Identify installed Thunderbird versionRun 'thunderbird --version' or check the package manager (e.g., 'rpm -q thunderbird' on RHEL)Affected if Version is earlier than 52.1.0
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Check if system runs RHEL with bundled Mozilla productsRun 'rpm -qa | grep -i firefox' or 'rpm -qa | grep -i thunderbird' to see if Red Hat bundled versions are installedAffected if RHEL 6.0, 7.0, 7.3, 7.4, or 7.5 with unpatched Mozilla packages is in use
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Determine exposure to trigger conditionsReview whether users process bidirectional Unicode text (Arabic, Hebrew) in web content or emails combined with CSS animationsAffected if Bidirectional text AND CSS animations are actively used in the browser/email client environment
The environment is affected if Firefox version is below 53.0 or Thunderbird version is below 52.1.0, and the system processes bidirectional Unicode text with CSS animations.
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 data52.1.053.0
Upgrade affected Mozilla products to version 52.1 (Thunderbird, Firefox ESR) or version 53 (Firefox) or later to receive the security patch.
Fix this in Enterprise Linux
Scoped from the published advisory
- Consultation2.0 h
- Implementation1.0 h
- Testing2.0 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 $1,696.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-5449 — 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-2017-5449 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
- No spam, self-promotion, credentials, or personal data