EUVD-2026-21233
GHSA-5jqq-xpcr-q3r7
Severity by source
CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/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:Green
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/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:Green
Lifecycle Timeline
4DescriptionCVE.org
X.509 date buffer overflow in wolfSSL_X509_notAfter / wolfSSL_X509_notBefore. A buffer overflow may occur when parsing date fields from a crafted X.509 certificate via the compatibility layer API. This is only triggered when calling these two APIs directly from an application, and does not affect TLS or certificate verify operations in wolfSSL.
AnalysisAI
wolfSSL versions before 5.9.1 contain a heap buffer overflow in the X.509 date parsing functions wolfSSL_X509_notAfter and wolfSSL_X509_notBefore when processing crafted certificates through the compatibility layer API. The vulnerability has a CVSS score of 2.3 with attack vector requiring adjacent network access and persistence, affecting only direct API calls and not standard TLS or certificate verification operations. No public exploit code or active exploitation has been identified at the time of analysis.
Technical ContextAI
The vulnerability resides in wolfSSL's X.509 certificate compatibility layer, specifically in the date field parsing logic used by the wolfSSL_X509_notAfter and wolfSSL_X509_notBefore API functions. The root cause is classified as CWE-122 (Heap-based Buffer Overflow), indicating improper bounds checking when copying or processing date values extracted from X.509 certificate structures. The affected component is part of wolfSSL's OpenSSL compatibility layer, which provides drop-in replacements for OpenSSL functions. The buffer overflow occurs during date field extraction from maliciously crafted X.509 certificates, but the vulnerability is isolated to these specific compatibility layer APIs and does not propagate to wolfSSL's core TLS operations or certificate verification mechanisms, which use separate code paths.
RemediationAI
Vendor-released patch: wolfSSL 5.9.1 and later. Organizations running wolfSSL should upgrade to version 5.9.1 or newer to remediate the vulnerability. For applications unable to immediately upgrade, restrict direct use of the wolfSSL_X509_notAfter and wolfSSL_X509_notBefore compatibility layer APIs to trusted certificate sources, or validate certificate inputs before passing them to these functions. Standard TLS operations and certificate verification using wolfSSL's native APIs are not affected and do not require special mitigation. Additional advisory information is available at https://nvd.nist.gov/vuln/detail/CVE-2026-5448.
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Same weakness CWE-122 – Heap-based Buffer Overflow
View allSame technique Heap Overflow
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External POC / Exploit Code
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