CVE & CISA-KEV Catalog

CVE-2026-6679

HIGH
7.5
CVSS v3
NVD

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.

How to fix

Remediation Available
wolfsslDebian
Fixed in:5.9.2-1CVE-2026-6679

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityNone
IntegrityNone
AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploit Intelligence

0.58%probability of exploitation in 30 days
44thpercentile

Moderate risk: more likely to be exploited than 44% of all known CVEs.

References

Vendor Advisory1

Related Vulnerabilities

Other CWE-190 (Integer Overflow) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2020-16040Medium6.5100%-Fix
CVE-2019-11477High7.599%-Fix
CVE-2023-44443High7.894%-Fix
CVE-2014-0569High9.392%--
CVE-2017-3599High7.590%-Fix
CVE-2023-21716Critical9.882%-Fix

Common questions

How do I fix CVE-2026-6679?

Upgrade wolfssl on debian unstable to 5.9.2-1 or later.

Is CVE-2026-6679 being actively exploited?

Not that we know of. CVE-2026-6679 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.58% is the estimated probability that it will be exploited in the next 30 days. That is higher than 44% of all scored CVEs.

How severe is CVE-2026-6679?

CVE-2026-6679 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-6679 affect?

Published advisories record a fix for wolfssl (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-27.