CVE-2026-93395
CVE-2026-93395 is a medium-severity vulnerability in Mongodb C Driver with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-191.
Key facts
- Severity: Medium (CVSS 3.x base score 5.3)
- CVSS v4: 6.9
- EPSS exploit prediction: 0% (32nd percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-191
- Affected product: Mongodb C Driver
- Published:
- Last modified:
Description
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.
Frequently asked questions
- What is CVE-2026-93395?
- 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 severe is CVE-2026-93395?
- CVE-2026-93395 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.
- Is CVE-2026-93395 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (32nd percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-93395?
- CVE-2026-93395 affects Mongodb C Driver. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-93395?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- When was CVE-2026-93395 published?
- CVE-2026-93395 was published on 2026-09-17 and last updated on 2026-09-25.
References
Affected products (1)
- cpe:2.3:a:mongodb:c_driver:*:*:*:*:*:mongodb:*:*
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