# OSV-2021-389: Bad-cast to tt_cmap_t' (aka 'struct _tt_cmap')_cairo_truetype_index_to_ucs4

> A bad cast in Cairo's TrueType font handling can cause a crash, potentially leading to denial of service for applications using the library.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Not stated
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 13 Feb 2021

## What is OSV-2021-389?

OSV-2021-389 is a memory corruption vulnerability in poppler, published on 13 Feb 2021. 

### Official description

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=30823

```
Crash type: Bad-cast
Crash state:
Bad-cast to tt_cmap_t' (aka 'struct _tt_cmap')_cairo_truetype_index_to_ucs4
_cairo_sub_font_glyph_lookup_unicode
_cairo_sub_font_map_glyph
```

## Which versions are affected by OSV-2021-389?

1 open source package ship an affected version, including poppler.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `poppler` | OSS-Fuzz | All versions | None |

## How do I fix OSV-2021-389?

No fix has been published for OSV-2021-389 yet. Limit exposure of the affected software until one is available.

## Is OSV-2021-389 being exploited?

There is no known exploitation of OSV-2021-389 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for OSV-2021-389 and fix it if it is affected.

What it is: OSV-2021-389 is a memory corruption vulnerability in poppler, published on 13 Feb 2021. 
Exploitation: There is no known exploitation of OSV-2021-389 in the wild and no public exploit code.

Affected packages and fixed versions:
- poppler (OSS-Fuzz): affected all versions; no fix listed

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/OSV-2021-389/ (Markdown: https://insights.sbomify.com/OSV-2021-389/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/OSV-2021-389

---
From sbomify Insights: https://insights.sbomify.com/OSV-2021-389/
Summaries are generated and may contain mistakes; the official description above is the record.