CVE Catalog

CVE-2026-96748

MediumCVSS 6.5
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.26%

16th percentile - higher than 16% of all known CVEs

Summary

PyMongo's connection string parsing decodes percent-encoded characters in the host portion before the host list is separated on its delimiters. When an application places a hostname value supplied by an unauthenticated party into a connection string, that party may cause additional servers of their choosing to be added to the application's database client. The application may then send its authentication exchange and database operations to one of those servers, which can observe limited information and return altered results.

Risk Assessment

The vulnerability may allow an attacker to redirect database traffic to a malicious server, potentially leading to leakage of authentication data or manipulation of query results. The risk applies to applications that insert untrusted input into connection strings.

Recommendation

Update PyMongo to a patched version or avoid placing untrusted input into connection strings. Implement validation and sanitization of input before using it in connection configuration.

Related vulnerabilities

Original NVD description (English source)

PyMongo's connection string parsing decodes percent-encoded characters in the host portion before the host list is separated on its delimiters. When an application places a hostname value supplied by an unauthenticated party into a connection string, that party may cause additional servers of their choosing to be added to the application's database client. The application may then send its authentication exchange and database operations to one of those servers, which can observe limited information and return altered results.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS