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ZbarApplication · Zbar Project

CVE-2023-40889

CRITICAL · 9.8 CVSS v3.1 Published 2023-08-29
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
A heap-based buffer overflow exists in the qr_reader_match_centers function of ZBar 0.23.90. Specially crafted QR codes may lead to information disclosure and/or arbitrary code execution. To trigger this vulnerability, an attacker can digitally input the malicious QR code, or prepare it to be physically scanned by the vulnerable scanner.

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

ZBar 0.23.90 contains a heap-based buffer overflow in the qr_reader_match_centers function when processing specially crafted QR codes. The vulnerability allows attackers to overwrite heap memory through malformed QR code input, potentially leading to information disclosure or arbitrary code execution.

MitigationUpdate ZBar to the latest patched version. If patching is not immediately possible, restrict QR code input sources and validate QR code data before processing.

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
ZbarApplication
Affected:= 0.23.90

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. Find ZBar installation
    Run 'dpkg -l | grep zbar' on Debian/Ubuntu, 'rpm -qa | grep -i zbar' on RHEL/CentOS, or check for libzbar.so files with 'find /usr -name "libzbar*" 2>/dev/null'
    Affected if No ZBar packages or libraries are found, meaning the product is not installed
  2. Determine ZBar version
    Run 'zbarimg --version' or check the library version with 'dpkg -l | grep zbar' or 'rpm -qi <package-name>'
    Affected if The installed version is 0.23.90 exactly
  3. Verify QR code processing is in use
    Search for applications using ZBar for QR scanning: check running processes for zbar-related binaries, or grep application configs for 'zbar' library linkage with 'ldd <application> | grep zbar'
    Affected if Applications link to libzbar and perform QR code decoding operations
  4. Confirm QR reader component is loaded
    Review application logs or code that initializes ZBar's QR code reader module, or inspect if the qr_reader subsystem is explicitly enabled in the application
    Affected if The QR code reader module (qr_reader) is initialized and active

The environment is affected if ZBar version 0.23.90 is installed and any application or service uses ZBar to process QR codes with the qr_reader_match_centers function enabled.

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.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update ZBar to the latest patched version. If patching is not immediately possible, restrict QR code input sources and validate QR code data before processing.

Recommended fix High confidence

ZBar >= 0.23.91 (or latest stable release such as 0.25.x)

  1. 1. Identify the ZBar library or application using the vulnerable version in your environment (check package managers, dependency files, or application bundles)
  2. 2. If using a package manager (apt, yum, dnf, pip, etc.), update to the latest available version: `apt update && apt upgrade zbar` or `dnf update zbar`
  3. 3. If using ZBar as a dependency in your own project, update the dependency specification to a version >= 0.23.91 (e.g., change version constraint to 'zbar >= 0.23.91' in your package.json, requirements.txt, or similar)
  4. 4. Rebuild and redeploy any applications that link against the ZBar library
  5. 5. Verify the fix by confirming the new ZBar version is installed: `zbarimg --version` or checking the library version

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Zbar 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-2023-40889 in production — separate from our analysis above.

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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