# CVE-2026-110599: L-SMASH through 2.14.5 Double Free in HEVC and H.264 Importer Probe

> Attackers can trigger a double free and heap corruption in L-SMASH by providing crafted media streams, leading to crashes or potential code execution.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 14 Oct 2026
- **Updated:** 14 Oct 2026
- **Also known as:** GHSA-4h8q-hwh6-8jpj

## What is CVE-2026-110599?

CVE-2026-110599 is a medium-severity use after free vulnerability in l-smash, published on 14 Oct 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

L-SMASH through 2.14.5 contains a double free vulnerability in hevc_setup_first_summary() and h264_setup_first_summary() in importer/nalu_imp.c that frees borrowed codec-specific objects on error paths. Attackers can supply a crafted Annex-B elementary stream lacking a parseable SPS to lsmash_read_file() or the boxdumper, remuxer, or muxer tools, causing use-after-free, heap corruption, and crashes.

Weakness: CWE-415 (Double Free)

## Which versions are affected by CVE-2026-110599?


## How do I fix CVE-2026-110599?

No fix has been published for CVE-2026-110599 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-110599 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-110599 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-110599 and fix it if it is affected.

What it is: CVE-2026-110599 is a medium-severity use after free vulnerability in l-smash, published on 14 Oct 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-110599 exists.

Affected product: l-smash. 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-2026-110599/ (Markdown: https://insights.sbomify.com/CVE-2026-110599/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-110599
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-110599
- OSV: https://osv.dev/vulnerability/CVE-2026-110599

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-110599/
Summaries are generated and may contain mistakes; the official description above is the record.