CVE-2026-6679 json
DTLS 1.3 ACK serialization heap buffer overflow via integer truncation
published 2026-06-25 4 mo ago modified 2026-07-25 3 mo ago also EUVD-2026-39557 , GHSA-c9q2-5c67-xg9p , JLSEC-2026-753
- cvss
- 7.5
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 43%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- julia wolfSSL_jll 5.9.2+0
- wolfssl wolfssl 5.9.1
- wolfssl Alpine 3.24 5.9.2-r0
alpine advisories ALPINE-CVE-2026-6679
Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0
- github.com/wolfSSL/wolfssl#10116 pull request
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 4 mo ago
Exploit prediction
0.51% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 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 |
| CNA | 4.0 | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| NVD | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| OSV | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| julia | wolfSSL_jll | >=5.7.2+0, <5.9.2+0 |
5.9.2+0 |
Affected products
- wolfSSL wolfSSL
Classification
References
-
github.com
/wolfSSL/wolfssl/pull/10116
patch, issue-tracking, web
-
wolfssl.com
/docs/security-vulnerabilities/
vendor-advisory, web
-
github.com
/advisories/GHSA-c9q2-5c67-xg9p
web
-
nvd.nist.gov
/vuln/detail/CVE-2026-6679
web
-
wolfssl.com
/docs/security-vulnerabilities
web
Sources
- CVE List CVE-2026-6679
- NVD CVE-2026-6679
- OSV JLSEC-2026-753
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.