CVE-2026-93395
MEDIUMDescription
A missing lower-bound validation in the bson_new_from_buffer() function of libbson allows an integer underflow when processing BSON data with a zero-length prefix. The function reads a 32-bit document length from the input buffer but does not verify that the value is at least 5 (the minimum valid BSON document size) before using it in an array index calculation. When the length field is zero, the expression used to check the document's null terminator wraps to UINT32_MAX, causing a heap out-of-bounds read that crashes the process. An unauthorized party who can supply crafted BSON input to an application using this API can cause a denial of service.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Exploit Intelligence
Low risk: more likely to be exploited than 32% of all known CVEs.
References
Related Vulnerabilities
Other CWE-191 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2014-0497 | Critical | 9.8 | 100% | KEV | Fix |
| CVE-2020-36228 | High | 7.5 | 85% | - | Fix |
| CVE-2020-36221 | High | 7.5 | 85% | - | Fix |
| CVE-2024-38063 | Critical | 9.8 | 71% | - | Fix |
| CVE-2017-14496 | High | 7.5 | 66% | - | Fix |
| CVE-2004-0184 | Medium | 5.0 | 60% | - | Fix |
Common questions
How do I fix CVE-2026-93395?
Upgrade mongo-c-driver on debian unstable to 2.4.0-1 or later.
Is CVE-2026-93395 being actively exploited?
Not that we know of. CVE-2026-93395 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.40% is the estimated probability that it will be exploited in the next 30 days. That is higher than 32% of all scored CVEs.
How severe is CVE-2026-93395?
CVE-2026-93395 has a CVSS v3 base score of 5.3, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-93395 affect?
Published advisories record a fix for mongo-c-driver (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-09-25.