Home/CVE/A heap-based buffer overflow exists in the qr_reader_match_centers function of ZBar 0.23.90. Specially crafted QR codes
CVE
CVE-2023-40889
A heap-based buffer overflow exists in the qr_reader_match_centers function of ZBar 0.23.90. Specially crafted QR codes
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.
CRITICAL · CVSS 9.8
EPSS 0.00814
Act now
- Public exploit or PoC is available
- CVSS base score ≥ 7.0
Sigma rules0
YARA rules0
Look this up elsewhere - one-click external pivots
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How to read a CVE - triage first, then detect and patch
This page is every public fact about CVE-2023-40889, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.
Triage: should I act now? Four signals, and they are not interchangeable:
CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked.
EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal.
CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score.
Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.
How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.
Then what - two workflows:
Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits.
PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.
Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).
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ATT&CK techniques
1Techniques this CVE enables - linked via CWECAPECATT&CK. High◆ = named directly in ATT&CK or Nuclei templates.
▤ Build a SIEM detection for these techniques⬡
Weakness Classification
CWE-787Out-of-bounds Write
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Affected Products & Versions
1zbar project zbarall versions
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Affected Packages
9Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
Debian:11
zbar
fixed in 0.23.90-1+deb11u1
Debian:12
zbar
fixed in 0.23.92-7+deb12u1
PyPI
zbar
CRITICAL
Ubuntu:20.04:LTS
zbar
Ubuntu:22.04:LTS
zbar
Ubuntu:24.04:LTS
zbar
Ubuntu:Pro:14.04:LTS
zbar
Ubuntu:Pro:16.04:LTS
zbar
Ubuntu:Pro:18.04:LTS
zbar
⚠
Public Exploits & PoCs
2These PoC and exploit links come from public sources and are not verified to be safe or functional. Review the code before running anything, and treat unverified entries as untrusted.
📦
Fixed versions by distribution
8The package version that resolves this CVE on each Linux distribution, from the vendor’s published security data. fixed in shows a patched version exists; open means the package is listed as affected with no fix yet.
alpine edgezbar fixed in 0.23.93-r0
alpine v3.19zbar fixed in 0.23.93-r0
alpine v3.20zbar fixed in 0.23.93-r0
suse sle15libzbar-devel fixed in 0:0.23.1-150300.3.3.1
suse sle15libzbar0 fixed in 0:0.23.1-150300.3.3.1
suse sle15libzbarqt-devel fixed in 0:0.23.1-150300.3.3.1
suse sle15libzbarqt0 fixed in 0:0.23.1-150300.3.3.1
suse sle15zbar fixed in 0:0.23.1-150300.3.3.1
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Scoring & Timeline
9.8
CRITICAL · CVSS v3.1 · [email protected]
Attack Vector
Network
Adjacent
Local
Physical
Attack Complexity
Low
High
Privileges Required
None
Low
High
User Interaction
None
Required
Scope
Unchanged
Changed
Confidentiality
None
Low
High
Integrity
None
Low
High
Availability
None
Low
High
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Vendor Advisories
3🔗
References & Sources
5Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.