Read the docs
TI-2026-03059 Aliases CVE-2026-3549GHSA-j2g5-52p7-mfpc

ECH parsing heap buffer overflow

Priority MEDIUM 45CWE-122Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
Present
Impact type
—
Confidentiality · integrity · availability
Low · Low · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00507 43rd percentileScored 2026-11-07
Fix Fixed wolfSSL (wofSSL): 5.9.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
wolfSSLwolfSSLbefore 5.9.05.9.0Patch availableCNA
  • wolfSSL VendorwolfSSL Affected before 5.9.0 Fixed in 5.9.0 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:wolfssl:wolfssl:*:*:*:*:*:*:*:*before 5.9.0VulnerablewolfSSL
  • cpe:2.3:a:wolfssl:wolfssl:*:*:*:*:*:*:*:* Versions before 5.9.0 Vulnerable ·wolfSSL

Remediation

  • Fix · CNA wolfSSL (wofSSL) Fixed in 5.9.0

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    wofSSL wolfSSL 5.9.0

    2 records Highest priority Priority MEDIUM 1 MEDIUM, 1 LOW

    Other records, highest priority first

    • TI-2026-02792 Integer Overflow in Certificate Chain AllocationPriority LOW 6
    Show all 2 records →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-3549
  2. 2026-10-03 Alias added: GHSA-j2g5-52p7-mfpc

References

Patch 1

  • TI-2024-00830 SEGV and out of bounds memory read from malicious packet CVSS 3.1CRITICAL 9.1
  • TI-2022-18557 In wolfSSL before 5.5.1, malicious clients can cause a buffer overflow during a TLS 1.3… CVSS 3.1HIGH 7.5
  • TI-2025-10943 Potential DoS Vulnerability through Multiple KeyShareEntry with Same Group in TLS 1.3 ClientHello CVSS 4.0MEDIUM 6.3
  • TI-2017-09737 wolfSSL Bleichenbacher/ROBOT CVSS 3.0HIGH 7.5
  • TI-2019-08902 wolfSSL 4.0.0 has a Buffer Overflow in DoPreSharedKeys in tls13.c when a current identity… CVSS 3.1CRITICAL 9.8
  • TI-2017-02021 Improper certificate validation in wolfSSL CVSS 3.1CRITICAL 9.8
See all 150 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences