CVE-2026-3549: wofSSL wolfSSL · Heap-based Buffer Overflow
Affects wofSSL wolfSSLSource CVE Database V5
Not known to be exploited · CVSS 8.3 High : upgrade to 5.9.0 soon.
Data as of 1 Nov 2026, 08:20 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 42% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.9.0
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:L/SI:L/SA:LExploitation evidence
Disclosed: evidence found.
CVE published 19 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 31 Oct 2026.
What to do
Upgrade wofSSL wolfSSL to 5.9.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| wofSSLwolfSSL | Affected
| Fixed in
|
GitHubwolfssl/wolfsslpkg:github/wolfssl/wolfsslOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Organizations should immediately audit their use of wolfSSL to determine if TLS 1.3 ECH is enabled. If ECH is enabled, it is recommended to disable this feature until a security patch addressing CVE-2026-3549 is released. Employ runtime protections such as heap memory protection mechanisms (e.g., ASLR, heap canaries) to reduce exploitation success. Conduct thorough testing of wolfSSL integrations to detect anomalous behavior or crashes related to TLS handshake processing. Network-level defenses like intrusion detection systems should be tuned to detect abnormal TLS handshake patterns that could indicate exploitation attempts. For embedded and IoT devices using wolfSSL, coordinate with vendors to ensure timely firmware updates. Finally, consider implementing layered security controls such as application whitelisting and strict network segmentation to limit potential attacker movement if exploitation occurs.
Description
Heap Overflow in TLS 1.3 ECH parsing. An integer underflow existed in ECH extension parsing logic when calculating a buffer length, which resulted in writing beyond the bounds of an allocated buffer. Note that in wolfSSL, ECH is off by default, and the ECH standard is still evolving.