CVE-2026-2646 Heap buffer overflow in session parsing with wolfSSL_d2i_SSL_SESSION() function
Heap buffer overflow in wolfSSL session parsing allows attackers to corrupt memory and potentially execute code via crafted session data.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-2646?
CVE-2026-2646 is a medium-severity memory corruption vulnerability in Wolfssl Wolfssl, published on 19 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A heap-buffer-overflow vulnerability exists in wolfSSL's wolfSSL_d2i_SSL_SESSION() function. When deserializing session data with SESSION_CERTS enabled, certificate and session id lengths are read from an untrusted input without bounds validation, allowing an attacker to overflow fixed-size buffers and corrupt heap memory. A maliciously crafted session would need to be loaded from an external source to trigger this vulnerability. Internal sessions were not vulnerable.
Which versions are affected by CVE-2026-2646?
It affects 1 product.
Products include Wolfssl Wolfssl.
How do I fix CVE-2026-2646?
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-2026-2646 being exploited?
There is no known exploitation of CVE-2026-2646 in the wild and no public exploit code.
Other vulnerabilities in Wolfssl Wolfssl
Sources
Also known as DEBIAN-CVE-2026-2646, GHSA-24vq-qfc5-qrmj, JLSEC-2026-702, UBUNTU-CVE-2026-2646.