Quick answers
- Is CVE-2026-126792 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-126792 being exploited in the wild.
- How severe is CVE-2026-126792?
- Medium severity, with a CVSS score of 4.7, published 13 November 2026.
- Which products and versions are affected?
- MongoDB libmongocrypt.
- Is there a fix for CVE-2026-126792?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-126792 attacked?
- It is attacked with local access, in a software library.
- Am I affected by CVE-2026-126792?
- Check whether you run MongoDB Libmongocrypt. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The vulnerability is an out-of-bounds heap write in libmongocrypt's key-management request builder, caused by use of a fixed-size output buffer without validation of the cryptographic key size supplied by a custom key-management callback. When an embedding application provides its own cryptographic callback implementation with oversized keys, data larger than the buffer is written past its end. Exploitation requires high-privilege access to configure the in-process key provider, and demonstrated impact is abnormal process termination due to memory corruption.
Affected products
- MongoDB libmongocrypt
Timeline
- 2026-11-13: disclosed