# CVE-2026-81523: Cross-tenant database retargeting via dot/NUL injection in namespace strings in libmongocrypt

> CVE-2026-81523: Cross-tenant database retargeting via dot/NUL injection in namespace strings in libmongocrypt. CVSS 4.4 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-81523
Last updated: 2026-09-17T13:59:18Z

- Published: 2026-08-27 18:32 UTC · Updated: 2026-09-17 13:59 UTC · Assigner: mongodb
- CVSS: 4.4 (CVSS 3.1) · Severity: Medium · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
- EPSS: 0.10%, 1th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-74

## Description

A missing input-validation issue in MongoDB libmongocrypt's automatic-encryption context setup allows a caller-supplied database identifier to be accepted without sanitization. The resulting impact is limited to incorrect schema selection, which may lead to limited disclosure or modification of information handled by the application.

## Affected vendors and products

- MongoDB: libmongocrypt

## Tracked companies

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

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-81523)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-81523)
- [https://github.com/mongodb/libmongocrypt/releases/tag/1.20.3](https://github.com/mongodb/libmongocrypt/releases/tag/1.20.3)
- [https://jira.mongodb.org/browse/MONGOCRYPT-977](https://jira.mongodb.org/browse/MONGOCRYPT-977)

---

_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/)_


---
Canonical: https://rewindex.com/cve/CVE-2026-81523 · Markdown: https://rewindex.com/cve/CVE-2026-81523.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-81523 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T03:12:34.157Z