dbcve.org
LibsixelApplication · Saitoha

CVE-2019-19638

CRITICAL · 9.8 CVSS v3.1 Published 2019-12-08
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
An issue was discovered in libsixel 1.8.2. There is a heap-based buffer overflow in the function load_pnm at frompnm.c, due to an integer overflow.

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 · moderate confidence

libsixel 1.8.2 contains a heap-based buffer overflow vulnerability in the load_pnm function in frompnm.c, caused by an integer overflow that allows writing beyond allocated buffer boundaries.

MitigationUpgrade to a patched version of libsixel that addresses the integer overflow in frompnm.c load_pnm function, or implement proper integer overflow checks and bounds validation before buffer allocations.

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
LibsixelApplication
Affected:= 1.8.2

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
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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 if libsixel is installed
    Run command: pkg-config --modversion libsixel or ls -la /usr/lib/libsixel* or check your package manager for libsixel
    Affected if libsixel is not found on the system
  2. Determine installed libsixel version
    Run: pkg-config --modversion libsixel, or check dpkg -l | grep libsixel, or rpm -qa | grep libsixel depending on your system
    Affected if version returned is exactly 1.8.2
  3. Verify the vulnerable binary exists
    Check for binaries that link to libsixel: ldd $(which img2sixel) 2>/dev/null | grep libsixel, or check /usr/lib/ for libsixel shared objects
    Affected if libsixel library files are present and version is 1.8.2
  4. Confirm frompnm.c component is in use
    Inspect if PNM/PNM-related image decoding is available: img2sixel --help or file /usr/lib/libsixel.so*
    Affected if libsixel with PNM image decoding capability is present and version is 1.8.2

The environment is affected if libsixel version 1.8.2 is installed and the load_pnm function in frompnm.c is accessible for processing PNM image files.

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 to a patched version of libsixel that addresses the integer overflow in frompnm.c load_pnm function, or implement proper integer overflow checks and bounds validation before buffer allocations.

Fix this in Libsixel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
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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-2019-19638 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