Quick answers
- Is CVE-2026-120803 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-120803 being exploited in the wild.
- How severe is CVE-2026-120803?
- High severity, with a CVSS score of 7.1, published 10 November 2026.
- Which products and versions are affected?
- MongoDB before 8.3.16, before 9.0.7.
- Is there a fix for CVE-2026-120803?
- Yes: fixed in MongoDB 8.3.16, 9.0.7. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-120803 attacked?
- It is attacked over the network, in a hosted service.
- Am I affected by CVE-2026-120803?
- Check whether you run MongoDB at an affected version. 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.
How to fix
- Fixed in: MongoDB 8.3.16, 9.0.7
Technical details
A use-after-free vulnerability exists in MongoDB's Slot-Based Execution (SBE) implementation for window function accumulators, specifically in $setWindowFields aggregation pipelines. When specific conditions occur, the accumulator retains a dangling pointer to freed memory; dereferencing this stale pointer during serialization of the carried-forward value causes a heap out-of-bounds read. An authenticated attacker with readWrite privileges can craft a malicious aggregation pipeline to trigger this condition.
Affected products
- MongoDB MongoDB before 8.3.16, before 9.0.7
Timeline
- 2026-11-10: disclosed
- 2026-10-20: patched: Fix version released