EUVD-2026-21228Severity by source
CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:H/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
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:H/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
4DescriptionCVE.org
A stack buffer overflow exists in wolfSSL's PKCS7 implementation in the wc_PKCS7_DecryptOri() function in wolfcrypt/src/pkcs7.c. When processing a CMS EnvelopedData message containing an OtherRecipientInfo (ORI) recipient, the function copies an ASN.1-parsed OID into a fixed 32-byte stack buffer (oriOID[MAX_OID_SZ]) via XMEMCPY without first validating that the parsed OID length does not exceed MAX_OID_SZ. A crafted CMS EnvelopedData message with an ORI recipient containing an OID longer than 32 bytes triggers a stack buffer overflow. Exploitation requires the library to be built with --enable-pkcs7 (disabled by default) and the application to have registered an ORI decrypt callback via wc_PKCS7_SetOriDecryptCb().
AnalysisAI
Stack buffer overflow in wolfSSL's PKCS7 implementation allows local attackers to cause a denial of service or potentially execute code by crafting a CMS EnvelopedData message with an oversized OID in an OtherRecipientInfo recipient structure. The vulnerability affects wolfSSL when compiled with --enable-pkcs7 (disabled by default) and only when an application explicitly registers an ORI decrypt callback, significantly limiting real-world exposure. No public exploit code or active exploitation has been identified at time of analysis.
Technical ContextAI
The vulnerability exists in the wc_PKCS7_DecryptOri() function in wolfcrypt/src/pkcs7.c, which processes CMS (Cryptographic Message Syntax) EnvelopedData structures defined in RFC 5652. When parsing an OtherRecipientInfo (ORI) recipient type within a PKCS7 message, the function uses XMEMCPY to copy an ASN.1-parsed OID directly into a fixed 32-byte stack buffer (oriOID[MAX_OID_SZ]) without validating the OID length first. This is a classic CWE-121 (Stack-based Buffer Overflow) vulnerability. The root cause is the lack of bounds checking before copying variable-length ASN.1 data into a fixed-size stack allocation. The attack surface is severely restricted because PKCS7 support is an optional compile-time feature (--enable-pkcs7, disabled by default) and exploitation additionally requires the host application to have registered an ORI decrypt callback via wc_PKCS7_SetOriDecryptCb(), making this a conditional vulnerability affecting only specialized deployments.
RemediationAI
Apply the upstream patch available in wolfSSL PR #10116 (https://github.com/wolfSSL/wolfssl/pull/10116), which adds bounds checking to the OID length before copying into the fixed buffer. If a patched release version is not yet available, apply the PR changes directly to the source. For applications that must remain on unpatched versions, disable PKCS7 support at compile time (do not use --enable-pkcs7) or avoid registering an ORI decrypt callback via wc_PKCS7_SetOriDecryptCb(). Monitor wolfSSL release notes and security advisories at https://www.wolfssl.com for an official patched release version.
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Same weakness CWE-121 – Stack-based Buffer Overflow
View allSame technique Buffer Overflow
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External POC / Exploit Code
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