Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

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CVE-2026-5295

Severity CVSS v4.0:
MEDIUM
Type:
CWE-121 Stack-based Buffer Overflow
Publication date:
09/04/2026
Last modified:
29/04/2026

Description

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().

Impact

Vector 4.0
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 CVSS v4.0 Severity and Metrics:

Base Score: 5.90 MEDIUM
Vector: 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

Attack Vector (AV): Adjacent
Attack Complexity (AC): Low
Attack Requirements (AT): Present
Privileges Required (PR): None
User Interaction (UI): Passsive
Confidentiality (VC): Low
Integrity (VI): Low
Availability (VA): High
Confidentiality (SC): None
Integrity (SI): None
Availability (SA): None

Base Score 4.0
5.90
Severity 4.0
MEDIUM
Vector 3.x
CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H CVSS v3.1 Severity and Metrics:

Base Score: 8.00 HIGH
Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Attack Vector (AV): Adjacent
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): Required
Scope (S): Unchanged
Confidentiality (C): High
Integrity (I): High
Availability (A): High

Base Score 3.x
8.00
Severity 3.x
HIGH

Vulnerable products and versions

CPE From Up to
cpe:2.3:a:wolfssl:wolfssl:*:*:*:*:*:*:*:* 5.9.1 (excluding)

To consult the complete list of CPE names with products and versions, see this page


References to Advisories, Solutions, and Tools