# CVE-2026-2656: ChaiScript type_info.hpp bare_equal use after free

> A use-after-free vulnerability in ChaiScript allows local attackers to potentially execute arbitrary code or cause denial of service.

- **Severity:** Low 2.0 (`CVSS:4.0/AV:L/AC:H/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:** 18 Feb 2026
- **Updated:** 23 Feb 2026
- **Also known as:** GHSA-rjm5-gmfm-6cp4

## What is CVE-2026-2656?

CVE-2026-2656 is a low-severity use after free vulnerability in ChaiScript, published on 18 Feb 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A flaw has been found in ChaiScript up to 6.1.0. This affects the function chaiscript::Type_Info::bare_equal of the file include/chaiscript/dispatchkit/type_info.hpp. This manipulation causes use after free. The attack requires local access. The attack's complexity is rated as high. The exploitability is reported as difficult. The exploit has been published and may be used. The project was informed of the problem early through an issue report but has not responded yet.

Weakness: CWE-416 (Use After Free), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2026-2656?

It affects 1 product.


Products: Chaiscript Chaiscript.

## How do I fix CVE-2026-2656?

No fix has been published for CVE-2026-2656 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-2656 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-2656 exists.

## Other vulnerabilities in ChaiScript

- [CVE-2026-3382](https://insights.sbomify.com/CVE-2026-3382/): ChaiScript boxed_number.hpp get_as memory corruption (medium 4.8)
- [CVE-2026-3383](https://insights.sbomify.com/CVE-2026-3383/): ChaiScript boxed_number.hpp go divide by zero (medium 4.8)
- [CVE-2026-3384](https://insights.sbomify.com/CVE-2026-3384/): ChaiScript chaiscript_eval.hpp Function_Push_Pop recursion (medium 4.8)
- [CVE-2026-2655](https://insights.sbomify.com/CVE-2026-2655/): ChaiScript chaiscript_defines.hpp operator use after free (low 2.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-2656 and fix it if it is affected.

What it is: CVE-2026-2656 is a low-severity use after free vulnerability in ChaiScript, published on 18 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-2026-2656 exists.

Affected product: ChaiScript. 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-2026-2656/ (Markdown: https://insights.sbomify.com/CVE-2026-2656/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-2656
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-2656
- OSV: https://osv.dev/vulnerability/CVE-2026-2656

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-2656/
Summaries are generated and may contain mistakes; the official description above is the record.