CVE-2026-6679 | A heap buffer overflow could occur in the DTLS 1.3 ACK seria… | CVSS 8.8 HIGH

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.

Metadata

CVE ID: CVE-2026-6679
State: PUBLISHED
Assigner: wolfSSL
Reserved: 2026-04-20 15:00 UTC
Published: 2026-06-25 20:13 UTC
Last updated: 2026-06-25 20:13 UTC
Primary CWE: CWE-787
CWE-787 Out-of-bounds Write
Vendor / Product: wolfSSL / wolfSSL
Sources: cve.org · NVD

Severity & Metrics

8.8 HIGH CVSS 4.0

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

Affected products (1)

Vendor	Product	Platform	Versions
wolfSSL	wolfSSL	—	5.4.0 ≤ 5.9.0

Weakness (CWE)

CWE	Source	Description
CWE-190	cna	CWE-190 Integer Overflow or Wraparound
CWE-197	cna	CWE-197 Numeric Truncation Error
CWE-787	cna	CWE-787 Out-of-bounds Write

CVSS scores (1)

Score	Severity	Version	Source	Vector
8.8	HIGH	4.0	cna	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

References (2)