CVE-2023-6936 json
Heap-buffer over-read with WOLFSSL_CALLBACKS
published 2024-02-20 2 y ago modified 2026-07-25 3 mo ago also EUVD-2023-59134 , GHSA-cwpg-8775-j56v , JLSEC-2026-678
- cvss
- 5.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.6%
- EPSS 0.6% chance of exploitation in 30 days, percentile 48%
- public exploits
- 0
- none known
Summary
In wolfSSL prior to 5.6.6, if callback functions are enabled (via the WOLFSSL_CALLBACKS flag), then a malicious TLS client or network attacker can trigger a buffer over-read on the heap of 5 bytes (WOLFSSL_CALLBACKS is only intended for debugging).
Patch / fix
- julia wolfSSL_jll 5.7.2+0
- wolfssl wolfssl 5.6.6
- wolfssl Debian 13 5.6.6-1.2
debian advisories DEBIAN-CVE-2023-6936
- github.com/wolfSSL/wolfssl#6949 pull request
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 2 y ago
Exploit prediction
0.60% chance of exploitation in the next 30 days, higher than 48% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N |
| NVD | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H |
| OSV | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| julia | wolfSSL_jll | <5.7.2+0 |
5.7.2+0 |
Affected products
- wolfSSL wolfSSL
Classification
References
-
github.com
/wolfSSL/wolfssl/pull/6949/
patch, issue-tracking, web
-
github.com
/wolfSSL/wolfssl/pull/6949
web
-
wolfssl.com
/docs/security-vulnerabilities/
vendor-advisory, web
-
github.com
/advisories/GHSA-cwpg-8775-j56v
web
-
nvd.nist.gov
/vuln/detail/CVE-2023-6936
web
-
wolfssl.com
/docs/security-vulnerabilities
web
Sources
- CVE List CVE-2023-6936
- NVD CVE-2023-6936
- OSV JLSEC-2026-678
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.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.