CVE-2026-96748: MongoDB Python Driver · Improper Handling of URL Encoding
Affects MongoDB Python DriverSource CVE Database V5
Not known to be exploited · CVSS 8.3 High : upgrade to 4.18.2 soon.
Data as of 6 Nov 2026, 23:24 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 30% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 4.18.2
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 24 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.
What to do
Upgrade Python Driver and pymongo to 4.18.2.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| MongoDBPython Driver | Affected
| Fixed in
|
PyPIpymongopkg:pypi/pymongoOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
If you cannot patch yet, applications should avoid incorporating untrusted or unauthenticated hostname values into MongoDB connection strings to prevent injection of malicious hosts.
Description
CVE-2026-96748 is a vulnerability in the PyMongo Python driver for MongoDB where improper handling of URL encoding in connection strings can allow an attacker to inject additional servers into the client's host list. This occurs because percent-encoded characters in the host portion are decoded before splitting the host list, enabling an unauthenticated party to manipulate the connection string. As a result, the application may send authentication and database operations to attacker-controlled servers, which can observe limited information and return altered results. The issue affects PyMongo versions from 0 up to but not including 4.18.2.