Security readout for executives and security teams
Plain-English summary
CVE-2023-6936 is a memory read flaw in wolfSSL before 5.6.6. It requires WOLFSSL_CALLBACKS, a debugging feature, to be enabled. A malicious TLS client or network attacker could read five bytes from heap memory. The reported impact is limited confidentiality exposure, not code execution or service disruption.
Executive priority
Treat as a targeted medium-priority dependency issue. It is unlikely to justify emergency response unless affected wolfSSL builds are internet-facing with debugging callbacks enabled, but it should be corrected during routine patching and product hardening.
Technical view
When wolfSSL is built with WOLFSSL_CALLBACKS, crafted TLS client interaction can trigger a CWE-126 heap buffer over-read of five bytes. The CVSS 3.1 score is 5.3: network reachable, low complexity, no privileges, no user interaction, with low confidentiality impact only.
Likely exposure
Likely exposure is limited to systems embedding or linking wolfSSL versions before 5.6.6 with WOLFSSL_CALLBACKS enabled. The source says this flag is intended for debugging, so typical production builds may be unaffected, but this must be verified in build and dependency inventories.
Exploitation context
The provided sources do not show active exploitation, and the CVE is not listed as KEV. The issue is remotely reachable only where an affected wolfSSL build processes attacker-controlled TLS client traffic with callbacks enabled.
Researcher notes
Key uncertainty is environmental: the CVE depends on WOLFSSL_CALLBACKS, not merely wolfSSL presence. Validate compile-time configuration and actual linked versions. Do not assume affected downstream products without evidence from their build configuration or vendor advisory.
Mitigation direction
- Upgrade wolfSSL to 5.6.6 or later where wolfSSL is embedded or linked.
- Remove WOLFSSL_CALLBACKS from production builds unless vendor guidance requires it.
- Track wolfSSL advisory and PR 6949 for downstream packaging status.
- Prioritize internet-facing TLS endpoints that use affected wolfSSL builds.
Validation and detection
- Inventory applications, firmware, and services that embed wolfSSL.
- Confirm the wolfSSL runtime or linked library version is below 5.6.6.
- Review compiler flags and build scripts for WOLFSSL_CALLBACKS.
- Check whether affected services accept untrusted TLS client connections.
- Record evidence of upgraded version or callbacks disabled.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-126: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2023-6936 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N3.91.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.3MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/wolfSSL/wolfssl/pull/6949/CVE reference · patch
- https://www.wolfssl.com/docs/security-vulnerabilities/CVE reference · vendor-advisory
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Buffer Over-read
Buffer Over-read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.