# CVE-2026-58496: ThorVG: Out-of-bounds Read in SFNT/TTF Font Loader via Memory API


- **Severity:** Medium 4.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 27 Oct 2026
- **Updated:** 27 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-58496, GHSA-crfw-c34f-vqrj, UBUNTU-CVE-2026-58496

## What is CVE-2026-58496?

CVE-2026-58496 is a medium-severity vulnerability in thorvg, published on 27 Oct 2026. 

### Official description

Thor Vector Graphics (ThorVG) is a production-ready vector graphics engine. Prior to 1.0.7, the `SFNT/TTF` font loader's `SfntLoader::gen` function in `tvgSfntLoader.cpp` reads `data[0] through data[3]` to identify the font type without first checking that the input buffer contains at least four bytes. Loading an undersized font directly from memory through public APIs such as `tvg::Text::load` causes an out-of-bounds read. Loading through a file path using `mmap` can mask the read because of page alignment; the memory-loading API directly exposes it. Depending on memory layout, a malformed short font may crash the consuming application or disclose adjacent heap memory. This issue is fixed in version 1.0.7.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-58496?


## How do I fix CVE-2026-58496?

No fix has been published for CVE-2026-58496 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-58496 being exploited?

There is no known exploitation of CVE-2026-58496 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-58496 and fix it if it is affected.

What it is: CVE-2026-58496 is a medium-severity vulnerability in thorvg, published on 27 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-58496 in the wild and no public exploit code.

Affected product: thorvg. 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-2026-58496/ (Markdown: https://insights.sbomify.com/CVE-2026-58496/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-58496
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-58496
- OSV: https://osv.dev/vulnerability/CVE-2026-58496

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-58496/
Summaries are generated and may contain mistakes; the official description above is the record.