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Debian LinuxOperating system · Debian

CVE-2016-1521

HIGH · 8.8 CVSS v3.0 Published 2016-02-13
Fix available
A fix is available. Upgrade to after 42.0 or later.
See remediation →
95/100
Remediation priority · Urgent
Remotely reachable No privileges

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
The directrun function in directmachine.cpp in Libgraphite in Graphite 2 1.2.4, as used in Mozilla Firefox before 43.0 and Firefox ESR 38.x before 38.6.1, does not validate a certain skip operation, which allows remote attackers to execute arbitrary code, obtain sensitive information, or cause a denial of service (out-of-bounds read and application crash) via a crafted Graphite smart font.

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

Memory corruption vulnerability in Libgraphite's directrun function in directmachine.cpp fails to validate a skip operation, allowing out-of-bounds reads when processing crafted Graphite smart fonts. This can lead to arbitrary code execution, information disclosure, or denial of service.

MitigationUpdate Mozilla Firefox to version 43.0 or later, or Firefox ESR to 38.6.1 or later. Until patched, avoid loading untrusted Graphite smart fonts.

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
Debian LinuxOperating system
Affected:= 7.0= 8.0
FirefoxWeb browser
Affected:<= 42.0= 38.0.1= 38.0.5= 38.1.0= 38.1.1= 38.2.0= 38.2.1= 38.3.0= 38.4.0= 38.5.0= 38.5.1= 38.5.2
FedoraOperating system
Affected:= 22= 23
Graphite2Application
Affected:<= 1.2.4
ThunderbirdApplication
Affected:<= 38.5.1

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
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 checks

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

  1. Check Graphite2 library version on Linux
    For Debian: dpkg -l | grep graphite2 or locate libgraphite. For Fedora: rpm -qa | grep graphite2
    Affected if Graphite2 version is 1.2.4 or lower, or version cannot be determined (vulnerable)
  2. Check Mozilla Firefox version
    Run firefox --version or check package manager: dpkg -l firefox (Debian) or rpm -qa firefox (Fedora)
    Affected if Firefox version is 42.0 or lower, or any of these: 38.0.1, 38.0.5, 38.1.0, 38.1.1, 38.2.0, 38.2.1, 38.3.0, 38.4.0, 38.5.0, 38.5.1, 38.5.2 (all vulnerable)
  3. Check Mozilla Thunderbird version
    Run thunderbird --version or check package manager: dpkg -l thunderbird (Debian) or rpm -qa thunderbird (Fedora)
    Affected if Thunderbird version is 38.5.1 or lower (vulnerable)
  4. Check Debian or Fedora system version
    Run cat /etc/debian_version (Debian) or cat /etc/fedora-release (Fedora)
    Affected if System is Debian 7.0 or 8.0, or Fedora 22 or 23 (all have vulnerable graphite2 packages)
  5. Determine if Graphite fonts can be loaded
    Search for .grc or .grd Graphite font files on the system: find / -name "*.grc" -o -name "*.grd" 2>/dev/null
    Affected if Graphite font files exist and applications using libgraphite are in use, enabling the vulnerable code path

You are affected if you have Graphite2 version 1.2.4 or lower, or Firefox/Thunderbird versions 38.x through 42.x as listed, running on Debian 7.0/8.0 or Fedora 22/23, and your system loads or can load Graphite smart fonts.

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 42.0
Interim mitigation

Update Mozilla Firefox to version 43.0 or later, or Firefox ESR to 38.6.1 or later. Until patched, avoid loading untrusted Graphite smart fonts.

Fix this in Debian Linux Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA6.0 h
30.0 hours of engineering $5,120
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Scan for this in your stack

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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-2016-1521 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