Double Free in OpenSSL TLS Cert Rev Path of MongoDB C Driver
CVE-2026-84964 Published on September 3, 2026
Heap corruption via OCSP request double free from crafted multi-URL certificate in TLS client
A double free in the OpenSSL-based TLS certificate revocation checking path of the MongoDB C Driver can be reached by a TLS endpoint that the client already trusts. During the handshake, specially formed certificate data can cause the same heap object to be released twice. An unauthenticated party acting as the trusted endpoint may cause the connecting client application to terminate unexpectedly.
Vulnerability Analysis
CVE-2026-84964 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity and availability.
Weakness Type
What is a Double-free Vulnerability?
The product calls free() twice on the same memory address, potentially leading to modification of unexpected memory locations. When a program calls free() twice with the same argument, the program's memory management data structures become corrupted. This corruption can cause the program to crash or, in some circumstances, cause two later calls to malloc() to return the same pointer. If malloc() returns the same value twice and the program later gives the attacker control over the data that is written into this doubly-allocated memory, the program becomes vulnerable to a buffer overflow attack.
CVE-2026-84964 has been classified to as a Double-free vulnerability or weakness.
Products Associated with CVE-2026-84964
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Affected Versions
MongoDB C Driver:- Version 1.17.0 and below 1.30.9 is affected.
- Version 2.0.0 and below 2.5.2 is affected.