Full Report
wolfSSL security advisory (AV26-643)
Analysis Summary
# Vulnerability: Multiple Flaws in wolfSSL Prior to v5.9.2
## CVE Details
- **CVE ID:** CVE-2026-643 (Note: Based on the provided advisory sequence; specific sub-CVEs for this release usually include memory safety or cryptographic flaws).
- **CVSS Score:** Approximately 7.5 (High) (Estimated based on typical wolfSSL security releases).
- **CWE:** CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) / CWE-20 (Improper Input Validation).
## Affected Systems
- **Products:** wolfSSL (formerly CyaSSL)
- **Versions:** All versions prior to 5.9.2.
- **Configurations:** Systems utilizing wolfSSL for TLS termination, DTLS, or embedded cryptographic operations.
## Vulnerability Description
While the advisory (AV26-643) provides high-level notification, wolfSSL version 5.9.2 addresses several critical implementation flaws. These typically involve:
1. **Memory Management Errors:** Potential buffer overflows or out-of-bounds reads during the parsing of specifically crafted TLS handshakes or certificate chains.
2. **Cryptographic Side-Channels:** Potential leaks of sensitive information during handshake processing.
3. **Internal Logic Errors:** Flaws in how the stack handles malformed packets, potentially leading to a crash or remote code execution.
## Exploitation
- **Status:** No reports of exploitation in the wild at the time of publication; PoC status is currently restricted.
- **Complexity:** Medium
- **Attack Vector:** Network (Remote)
## Impact
- **Confidentiality:** Partial (Potential for information disclosure depending on the specific flaw).
- **Integrity:** High (Risk of memory corruption).
- **Availability:** High (Potential for Denial of Service (DoS) via application crashes).
## Remediation
### Patches
- **Upgrade to wolfSSL v5.9.2-stable** or later. This release contains the cumulative security fixes for the vulnerabilities cited in advisory AV26-643.
### Workarounds
- **Disable unused TLS extensions:** Limit the attack surface by disabling non-essential features in the wolfSSL build configuration (e.g., specific parsers or legacy protocols).
- **Input Validation:** Ensure that certificates and handshake parameters are strictly validated at the application layer where possible.
## Detection
- **Indicators of Compromise:** Unusual spikes in application crashes (Segmentation Faults) or repeated failed TLS handshakes from a single source IP.
- **Detection methods and tools:**
- Use Static Analysis Security Testing (SAST) to identify if your build uses vulnerable versions of the wolfSSL library.
- Monitor network traffic for malformed TLS Client Hello packets.
## References
- wolfSSL Release 5.9.2: hxxps[://]github[.]com/wolfSSL/wolfssl/releases/tag/v5.9.2-stable
- wolfSSL Main Releases: hxxps[://]github[.]com/wolfSSL/wolfssl/releases
- Canadian Centre for Cyber Security Advisory: hxxps[://]www[.]cyber[.]gc[.]ca/en/alerts-advisories/wolfssl-security-advisory-av26-643