# CVE-2026-120956: remote abort and memory disclosure from a malformed cursor.ns

Status: published. Published: 2026-11-03. Updated: 2026-11-03.

The MongoDB C Driver does not validate the type or format of a namespace field returned by the server in a query response. A MongoDB endpoint that a client application connects to, without needing any credentials, can return a malformed value in that field. This causes the client application process to terminate, and can also cause the driver to read memory outside an allocated buffer and to send a small amount of the application's own uninitialized heap memory back to the endpoint in a follow-up command. The impact is limited to the process that embeds the driver.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- MongoDB / C Driver: ≥ 1.25.0; ≤ 1.30.14 (affected, semver); ≥ 2.0.0; ≤ 2.5.7 (affected, semver). Source: CNA: mongodb

## Severity and prioritization

- CVSS 4.0: 7.1 (high); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N; source: CNA: mongodb

- CVSS 3.1: 7.1 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H; source: CNA: mongodb

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-617

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://jira.mongodb.org/browse/CDRIVER-6501 (CNA: mongodb)

## Provenance

- CNA: mongodb: https://www.cve.org/CVERecord?id=CVE-2026-120956; retrieved 2026-11-03; source updated 2026-11-03

Revision: d71d55148967c89fab95552fda3dd14212f54ebf70c3d89d923dc8fa14f10362

Canonical: https://y2.dev/cve/CVE-2026-120956

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