# CVE-2026-2660: FascinatedBox lily lily_symtab.c shorthash_for_name use after free

> A use-after-free vulnerability in the Lily programming language allows local attackers to potentially execute arbitrary code or escalate privileges.

- **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:** 18 Feb 2026
- **Updated:** 23 Feb 2026
- **Also known as:** GHSA-cq5p-w4x6-m6h3

## What is CVE-2026-2660?

CVE-2026-2660 is a medium-severity use after free vulnerability in FascinatedBox lily, 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 vulnerability was identified in FascinatedBox lily up to 2.3. Affected by this issue is the function shorthash_for_name of the file src/lily_symtab.c. The manipulation leads to use after free. Local access is required to approach this attack. The exploit is publicly available and might 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-2026-2660?

It affects 1 product.


Products: Lily-Lang Lily.

## How do I fix CVE-2026-2660?

No fix has been published for CVE-2026-2660 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-2660 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-2660 exists.

## Other vulnerabilities in FascinatedBox lily

- [CVE-2026-3390](https://insights.sbomify.com/CVE-2026-3390/): FascinatedBox lily Error Reporting lily_build_error.c patch_line_end out-of-bounds (medium 4.8)
- [CVE-2026-3391](https://insights.sbomify.com/CVE-2026-3391/): FascinatedBox lily lily_emitter.c clear_storages out-of-bounds (medium 4.8)
- [CVE-2026-3392](https://insights.sbomify.com/CVE-2026-3392/): FascinatedBox lily lily_emitter.c eval_tree null pointer dereference (medium 4.8)
- [CVE-2026-2662](https://insights.sbomify.com/CVE-2026-2662/): FascinatedBox lily lily_emitter.c count_transforms out-of-bounds (medium 4.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-2660 and fix it if it is affected.

What it is: CVE-2026-2660 is a medium-severity use after free vulnerability in FascinatedBox lily, 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-2026-2660 exists.

Affected product: FascinatedBox lily. 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-2026-2660/ (Markdown: https://insights.sbomify.com/CVE-2026-2660/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-2660
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-2660
- OSV: https://osv.dev/vulnerability/CVE-2026-2660

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-2660/
Summaries are generated and may contain mistakes; the official description above is the record.