Severity by source
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Lifecycle Timeline
6DescriptionCVE.org
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.
AnalysisAI
Integer underflow in TLS 1.3 ECH (Encrypted Client Hello) extension parsing within wolfSSL allows remote attackers to trigger heap buffer overflow conditions with availability impact through specially crafted network packets. While ECH is disabled by default in wolfSSL and the specification remains unstable, exploitation requires no authentication and succeeds under specific timing conditions. No patch is currently available for this vulnerability.
Technical ContextAI
A buffer overflow occurs when data written to a buffer exceeds its allocated size, potentially overwriting adjacent memory and corrupting program state. This vulnerability is classified as Heap-based Buffer Overflow (CWE-122).
RemediationAI
Use memory-safe languages or bounds-checked functions. Enable ASLR, DEP/NX, and stack canaries. Apply vendor patches promptly.
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Same weakness CWE-122 – Heap-based Buffer Overflow
View allSame technique Buffer Overflow
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External POC / Exploit Code
Leaving vuln.today
EUVD-2026-13168