# CVE-2023-40889: Heap-based buffer overflow in ZBar

> A heap-based buffer overflow in ZBar allows attackers to execute arbitrary code or disclose information via crafted QR codes.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 29 Aug 2023
- **Updated:** 4 Nov 2025
- **Also known as:** DEBIAN-CVE-2023-40889, GHSA-mhp6-jvpx-2p4m, PYSEC-2026-576, UBUNTU-CVE-2023-40889

## What is CVE-2023-40889?

CVE-2023-40889 is a critical memory corruption vulnerability in n/a, published on 29 Aug 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2023-40889?

3 open source packages ship an affected version, including zbar. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `zbar` | PyPI | All versions to 0.23.90 | None |
| `zbar` | PyPI | All versions to 0.23.90 | None |
| `zbar` | PyPI | All versions to 0.23.90 | None |

Products: Zbar Project Zbar.

## How do I fix CVE-2023-40889?

Upgrade to a fixed version.

## Is CVE-2023-40889 being exploited?

There is no known exploitation of CVE-2023-40889 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2023-40890](https://insights.sbomify.com/CVE-2023-40890/): Memory corruption in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-40889 and fix it if it is affected.

What it is: CVE-2023-40889 is a critical memory corruption vulnerability in n/a, published on 29 Aug 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-40889 in the wild and no public exploit code.

Affected packages and fixed versions:
- zbar (PyPI): affected all versions up to 0.23.90; no fix listed
- zbar (PyPI): affected all versions up to 0.23.90; no fix listed
- zbar (PyPI): affected all versions up to 0.23.90; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2023-40889/ (Markdown: https://insights.sbomify.com/CVE-2023-40889/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-40889
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-40889
- OSV: https://osv.dev/vulnerability/CVE-2023-40889

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-40889/
Summaries are generated and may contain mistakes; the official description above is the record.