EUVD-2026-21293
GHSA-m77r-vqw2-hffx
CVSS Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/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:X
Lifecycle Timeline
3Description
wolfSSL's wc_PKCS7_DecodeAuthEnvelopedData() does not properly sanitize the AES-GCM authentication tag length received and has no lower bounds check. A man-in-the-middle can therefore truncate the mac field from 16 bytes to 1 byte, reducing the tag check from 2⁻¹²⁸ to 2⁻⁸.
Analysis
Man-in-the-middle attackers can truncate AES-GCM authentication tags in wolfSSL's PKCS7 AuthEnvelopedData processing from 16 bytes to 1 byte, degrading cryptographic integrity verification from 2⁻¹²⁸ to 2⁻⁸ probability. Affects wolfSSL versions through 5.9.0 due to missing lower bounds validation in wc_PKCS7_DecodeAuthEnvelopedData(). …
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Remediation
Within 24 hours: Inventory all applications and systems using wolfSSL, specifically identifying those processing PKCS7 AuthEnvelopedData structures; communicate findings to application owners. Within 7 days: Implement network segmentation and monitoring to detect anomalous AES-GCM tag modifications; evaluate migration to alternative cryptographic libraries or isolated deployment environments. …
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External POC / Exploit Code
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