Quick answers
- Is CVE-2026-79516 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-79516 being exploited in the wild.
- How severe is CVE-2026-79516?
- Medium severity, with a CVSS score of 4, published 9 September 2026.
- Which products and versions are affected?
- Nothings Stb commit 31c1ad3 and prior.
- Is there a fix for CVE-2026-79516?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-79516 attacked?
- It is attacked with local access, in a software library.
- Am I affected by CVE-2026-79516?
- Check whether you run Nothings Stb at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
An out-of-bounds write vulnerability exists in stbsp_vsnprintf() (stb_sprintf.h) when called with count=0 and a non-NULL buffer. The null-termination logic computes a negative offset (l = -1), writing buf[-1] = 0. The root cause is missing bounds validation: when count=0, the internal callback clamps output to 0 bytes, but the subsequent null-terminator write does not account for this edge case. Attack vector requires calling stbsp_snprintf() with adversarial count and buffer parameters; no network reachability or authentication is required. An attacker can corrupt heap or stack memory adjacent to the target buffer. A patch is pending; workarounds include validating count > 0 before calling stbsp_snprintf().
Affected products
- nothings stb commit 31c1ad3 and prior
Timeline
- 2026-06-06: disclosed: Issue reported on GitHub #1963
- 2026-09-09: advisory: CVE-2026-79516 published