CVE-2026-3548: Buffer overflow in CRL number parsing in wolfSSL

Vulnerability summary

CVE-2026-3548 is a critical (CVSS 9.8) Heap-based Buffer Overflow vulnerability in wolfssl. EPSS estimates a 0.49% chance of exploitation in the next 30 days, higher than 42.1% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 19-03-2026
   PublishedVulnerability first disclosed.
2. 19-03-2026
   Last modifiedVulnerability information updated.

Description

Two buffer overflow vulnerabilities existed in the wolfSSL CRL parser when parsing CRL numbers: a heap-based buffer overflow could occur when improperly storing the CRL number as a hexadecimal string, and a stack-based overflow for sufficiently sized CRL numbers. With appropriately crafted CRLs, either of these out of bound writes could be triggered. Note this only affects builds that specifically enable CRL support, and the user would need to load a CRL from an untrusted source.

• CWE-122Heap-based Buffer OverflowThe product writes past the end of a buffer that was allocated on the heap.
• CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.