Medium severity · published Aug 27, 2026
CVE-2026-81523
Cross-tenant database retargeting via dot/NUL injection in namespace strings in libmongocrypt
4.4
CVSS
0.1%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.1% · higher than 1% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MO
MongoDB · MongoDB
1.0.0 before 1.20.3 · source: vendor
LI
Libmongocrypt · Mongodb
before 1.20.3 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-81523
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-81523
Product
https://github.com/mongodb/libmongocrypt/releases/tag/1.20.3
Vendor Advisory
https://jira.mongodb.org/browse/MONGOCRYPT-977
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