# CVE-2026-84964: Heap corruption via OCSP request double free from crafted multi-URL certificate in TLS client

> CVE-2026-84964: Heap corruption via OCSP request double free from crafted multi-URL certificate in TLS client. CVSS 5.9 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-84964
Last updated: 2026-09-22T16:19:25Z

- Published: 2026-09-03 15:02 UTC · Updated: 2026-09-22 16:19 UTC · Assigner: mongodb
- CVSS: 5.9 (CVSS 3.1) · Severity: Medium · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS: 0.26%, 17th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-415

## Description

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.

## Affected vendors and products

- MongoDB: C Driver

## Tracked companies

- [MongoDB Atlas](https://rewindex.com/company/mongodb-atlas.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-84964)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-84964)
- [https://jira.mongodb.org/browse/CDRIVER-6409](https://jira.mongodb.org/browse/CDRIVER-6409)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2026-84964 · Markdown: https://rewindex.com/cve/CVE-2026-84964.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-84964 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T03:12:44.671Z