CVE-2026-5295 Stack Buffer Overflow in wolfSSL PKCS7 wc_PKCS7_DecryptOri() via Oversized OID
A stack buffer overflow in wolfSSL allows code execution when processing crafted PKCS7 messages with oversized OIDs, requiring specific build and callback configurations.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-5295?
CVE-2026-5295 is a medium-severity memory corruption vulnerability in Wolfssl Wolfssl, published on 9 Apr 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official 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().
Weakness: CWE-121
Which versions are affected by CVE-2026-5295?
It affects 1 product.
Products include Wolfssl Wolfssl.
How do I fix CVE-2026-5295?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-5295 being exploited?
There is no known exploitation of CVE-2026-5295 in the wild and no public exploit code.
Other vulnerabilities in Wolfssl Wolfssl
Sources
Also known as DEBIAN-CVE-2026-5295, GHSA-fgx8-q3cf-p457, JLSEC-2026-719, UBUNTU-CVE-2026-5295.