CVE catalog
CVE-2026-6679
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
- Severity
- High · CVSS 8.8
- Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.51% · Oct 25, 2026
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.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | wolfssl | sid | 5.9.2-1.2 | fixed |
| Debian | wolfssl | trixie | 5.7.2-0.1+deb13u2 | vulnerable |
| Debian | wolfssl | bookworm | 5.5.4-2+deb12u2 | vulnerable |
| Debian | wolfssl | bookworm-security | 5.5.4-2+deb12u3 | vulnerable |
| Cpe | wolfssl | Not reported | Not reported | vulnerable |
| Cpe | wolfssl | Not reported | 5.9.1 | fixed |
| Ubuntu | wolfssl | 16.04 | 3.4.8+dfsg-1 | vulnerable |
| Ubuntu | wolfssl | 18.04 | 3.10.2+dfsg-2 | vulnerable |
| Ubuntu | wolfssl | 18.04 | 3.12.0+dfsg-1 | vulnerable |
| Ubuntu | wolfssl | 18.04 | 3.12.2+dfsg-1 | vulnerable |
| Ubuntu | wolfssl | 18.04 | 3.13.0+dfsg-1 | vulnerable |
| Ubuntu | wolfssl | 20.04 | 4.1.0+dfsg-2 | vulnerable |
| Ubuntu | wolfssl | 20.04 | 4.2.0+dfsg-1 | vulnerable |
| Ubuntu | wolfssl | 20.04 | 4.2.0+dfsg-2 | vulnerable |
| Ubuntu | wolfssl | 20.04 | 4.2.0+dfsg-3 | vulnerable |
| Ubuntu | wolfssl | 20.04 | 4.3.0+dfsg-2 | vulnerable |
| Ubuntu | wolfssl | 22.04 | 4.6.0-3 | vulnerable |
| Ubuntu | wolfssl | 22.04 | 5.0.0-1 | vulnerable |
| Ubuntu | wolfssl | 22.04 | 5.1.1-1 | vulnerable |
| Ubuntu | wolfssl | 22.04 | 5.2.0-1 | vulnerable |
| Ubuntu | wolfssl | 22.04 | 5.2.0-2 | vulnerable |
| Ubuntu | wolfssl | 24.04 | 5.5.4-2 | vulnerable |
| Ubuntu | wolfssl | 24.04 | 5.5.4-2.1 | vulnerable |
| Ubuntu | wolfssl | 24.04 | 5.6.4-2 | vulnerable |
| Ubuntu | wolfssl | 24.04 | 5.6.6-1.2 | vulnerable |
| Ubuntu | wolfssl | 24.04 | 5.6.6-1.3 | vulnerable |
| Ubuntu | wolfssl | 24.04 | 5.6.6-1.3build1 | vulnerable |
| Ubuntu | wolfssl | 25.10 | 5.7.2-0.1 | vulnerable |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | wolfssl | source | sid | 5.9.2-1 | not yet assigned | Not reported | Not reported |
| Debian | wolfssl | source | trixie | (unfixed) | not yet assigned | Not reported | Not reported |
| Debian | wolfssl | source | bookworm | (unfixed) | end-of-life | Not reported | Not reported |
| Cpe | wolfssl | cpe | Not reported | 5.9.1 | Not reported | Not reported | Not reported |
Notes
[trixie] wolfssl: Minor issue
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [libwolfssl35]Affected
Source package: [wolfssl]
Details (4)
5.5.4-2+deb12u2· amd64 · bookwormAffected
nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
5.5.4-2+deb12u2· arm64 · bookwormAffected
nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
5.5.4-2+deb12u3· amd64 · bookworm-securityAffected
nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
5.5.4-2+deb12u3· arm64 · bookworm-securityAffected
nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
- [libwolfssl-dev]Affected
Source package: [wolfssl]
Details (4)
5.5.4-2+deb12u2· amd64 · bookwormAffected
nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
5.5.4-2+deb12u2· arm64 · bookwormAffected
nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
5.5.4-2+deb12u3· amd64 · bookworm-securityAffected
nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
5.5.4-2+deb12u3· arm64 · bookworm-securityAffected
nvd · wolfssl · debian · bookworm; nvd · wolfssl · debian · 12
[Debian 13 (Trixie)]
- [libwolfssl42t64]Affected
Source package: [wolfssl]
Details (2)
5.7.2-0.1+deb13u1· amd64 · trixieAffected
nvd · wolfssl · debian · 13
5.7.2-0.1+deb13u1· arm64 · trixieAffected
nvd · wolfssl · debian · 13
- [libwolfssl-dev]Affected
Source package: [wolfssl]
Details (2)
5.7.2-0.1+deb13u1· amd64 · trixieAffected
nvd · wolfssl · debian · 13
5.7.2-0.1+deb13u1· arm64 · trixieAffected
nvd · wolfssl · debian · 13
Observed:
References
- [https://nvd.nist.gov/vuln/detail/CVE-2026-6679]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-6679]
- [https://osv.dev/vulnerability/UBUNTU-CVE-2026-6679]
- [https://security-tracker.debian.org/tracker/CVE-2026-6679]
[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database]