# CVE-2026-2242: janet-lang janet specials.c janetc_if out-of-bounds

> A local attacker can trigger an out-of-bounds read in the Janet interpreter's conditional logic, potentially exposing memory or causing a crash.

- **Severity:** Medium 4.8 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 9 Feb 2026
- **Updated:** 23 Feb 2026
- **Also known as:** GHSA-j4rx-v32x-q49g

## What is CVE-2026-2242?

CVE-2026-2242 is a medium-severity memory corruption vulnerability in janet-lang janet, published on 9 Feb 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

Weakness: CWE-125 (Out-of-bounds Read), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2026-2242?

It affects 1 product.


Products: Janet-Lang Janet.

## How do I fix CVE-2026-2242?

No fix has been published for CVE-2026-2242 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-2242 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-2242 exists.

## Other vulnerabilities in janet-lang janet

- [CVE-2022-30763](https://insights.sbomify.com/CVE-2022-30763/): Janet before 1.22.0 mishandles arrays. (high 7.5)
- [CVE-2026-2869](https://insights.sbomify.com/CVE-2026-2869/): janet-lang janet handleattr specials.c janetc_varset out-of-bounds (medium 4.8)
- [CVE-2026-2240](https://insights.sbomify.com/CVE-2026-2240/): janet-lang janet compile.c janetc_pop_funcdef out-of-bounds (medium 4.8)
- [CVE-2026-2241](https://insights.sbomify.com/CVE-2026-2241/): janet-lang janet os.c os_strftime out-of-bounds (medium 4.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-2242 and fix it if it is affected.

What it is: CVE-2026-2242 is a medium-severity memory corruption vulnerability in janet-lang janet, published on 9 Feb 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-2242 exists.

Affected product: janet-lang janet. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-2242/ (Markdown: https://insights.sbomify.com/CVE-2026-2242/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-2242
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-2242
- OSV: https://osv.dev/vulnerability/CVE-2026-2242

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-2242/
Summaries are generated and may contain mistakes; the official description above is the record.