# CVE-2026-18393: Ffmpeg: ffmpeg: heap buffer overflow in tdsc_load_cursor() via cur_fmt_mono cursor

> A heap buffer overflow in FFmpeg allows remote attackers to execute arbitrary code or cause denial of service via crafted video files.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:H`)
- **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:** Yes
- **Published:** 28 Aug 2026
- **Updated:** 28 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-18393, ECHO-1c69-349a-b2ee, GHSA-2g8r-jjgv-h39x, UBUNTU-CVE-2026-18393, openSUSE-SU-2026:11795-1

## What is CVE-2026-18393?

CVE-2026-18393 is a medium-severity memory corruption vulnerability in Red Hat Enterprise Linux AI (RHEL AI) 3, published on 28 Aug 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

A flaw was found in FFmpeg. The tdsc_load_cursor() function writes beyond
the bounds of a heap-allocated buffer when processing crafted TDSC cursor
data. A remote attacker could exploit this by supplying a specially crafted
video file, potentially leading to a denial of service or arbitrary code
execution.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-18393?


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `ffmpeg-9` | openSUSE:Tumbleweed | All versions | 9.0.1-6.1 |

## How do I fix CVE-2026-18393?

Apply the vendor's patch.

## Is CVE-2026-18393 being exploited?

There is no known exploitation of CVE-2026-18393 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-18393 and fix it if it is affected.

What it is: CVE-2026-18393 is a medium-severity memory corruption vulnerability in Red Hat Enterprise Linux AI (RHEL AI) 3, published on 28 Aug 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: There is no known exploitation of CVE-2026-18393 in the wild and no public exploit code.

Affected product: Red Hat Enterprise Linux AI (RHEL AI) 3. 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-2026-18393/ (Markdown: https://insights.sbomify.com/CVE-2026-18393/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-18393
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-18393
- OSV: https://osv.dev/vulnerability/CVE-2026-18393

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-18393/
Summaries are generated and may contain mistakes; the official description above is the record.