EmacsApplication · Gnu

CVE-2007-6109

HIGH · 10.0 CVSS v2.0 Published 2007-12-07
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
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
Stack-based buffer overflow in emacs allows user-assisted attackers to cause a denial of service (application crash) and possibly have unspecified other impact via a large precision value in an integer format string specifier to the format function, as demonstrated via a certain "emacs -batch -eval" command line.

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

Stack-based buffer overflow in Emacs triggered by providing a large precision value in an integer format string specifier to the format function. When running in batch mode with a crafted -eval argument, the oversized precision value overflows a stack buffer, causing a crash or potentially allowing arbitrary code execution.

MitigationUpgrade Emacs to a version that includes bounds checking on format string precision values, or implement input validation to reject precision values exceeding safe thresholds before passing to the format function.

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
EmacsApplication
Affected:all versions

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
Complete
Integrity
Complete
Availability
Complete

AV:N/AC:L/Au:N/C:C/I:C/A:C

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. Confirm Emacs is installed
    Run `emacs --version` or `which emacs` to verify Emacs is present on the system
    Affected if Emacs is installed and the version cannot be confirmed to include bounds checking (all known versions are affected)
  2. Check Emacs version
    Run `emacs --version` to retrieve the installed version number
    Affected if The installed version is any release of Gnu Emacs (all versions are affected per CVE)
  3. Identify batch mode usage
    Review any scripts or automation that invoke Emacs with `emacs --batch` or `emacs -eval` arguments
    Affected if Emacs is invoked in batch mode with user-controlled format strings passed to the -eval argument
  4. Audit format function calls
    Search source files or scripts for format function calls that accept precision values from external input (e.g., `(format "%.*d" precision value)`)
    Affected if The format function receives precision values from untrusted input without validation

The environment is affected if Emacs is installed and processes format strings with large precision values, particularly in batch mode via -eval arguments.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade Emacs to a version that includes bounds checking on format string precision values, or implement input validation to reject precision values exceeding safe thresholds before passing to the format function.

Fix this in Emacs Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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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-2007-6109 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