# CVE-2026-6679

## Summary

- **CVE ID:** CVE-2026-6679
- **Severity:** HIGH
- **CVSS Score:** 8.8 (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)
- **CWE:** CWE-787, CWE-190, CWE-197
- **Published:** Jun 25, 2026
- **Last Modified:** Jun 26, 2026

## Description

A heap buffer overflow could occur in the DTLS 1.3 ACK serialization path before the connecting peer is authenticated. The buffer overflow was due to an integer truncation when computing the length of the ACK record-number list, causing an undersized buffer to be allocated and then overrun. This affects builds using DTLS 1.3 and wolfSSL version 5.9.0 and earlier. A fix was added to the 5.9.1 release.

## Affected Products

- wolfSSL — wolfSSL (5.4.0)

## References

- [CNA](https://github.com/wolfSSL/wolfssl/pull/10116)
- [CNA](https://www.wolfssl.com/docs/security-vulnerabilities/)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.51%
- **EPSS Percentile:** 41.5

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._