vulnerability / NVI-00011849 / Revision 3
PyMongo: PYTHON-5990 Forced Unix domain socket connection via a .sock KMS endpoint in client-side field level encryption
GitHub lists this reviewed advisory for pymongo. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
5 medium
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
5 MEDIUM (3.1)
cna@mongodb.com severity; no combined Null risk score.
5.3 MEDIUM (4.0)
cna@mongodb.com severity; no combined Null risk score.
0.190%
FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.08665. Missing scores are unknown.
As of · FIRST EPSS
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
pymongo
source listed>= 3.9.0, <= 4.18.1
### Summary PyMongo passed the KMS endpoint of a data key verbatim into `parse_host()`, which returns any string ending in `.sock` unchanged instead of validating it as a hostname and port. The driver's connection code then treats such an address as a Unix domain socket path and connects to it with `AF_UNIX`. Because the endpoint originates from `masterKey.endpoint` in a key vault document, a party who can write to the key vault could redirect the driver's KMS connection to an arbitrary Unix domain socket path on the application host. ### Impact An application using client-side field level encryption (CSFLE) or Queryable Encryption is affected if an attacker can write to its key vault collection. Setting `masterKey.endpoint` on a data key to a `.sock`-suffixed string causes the next KMS request for that key (key cache TTL is ~60 seconds) to open an `AF_UNIX` connection to the attacker-chosen filesystem path from inside the victim application process. The documented custom KMS endpoint feature supports TCP hosts only, so this crosses a boundary the feature was never intended to allow. Impact is limited to the side effects of the connection itself. The socket is still wrapped in
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. FIRST EPSS
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
- NVD lastModified does not establish freshness of every associated CPE record.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-qx36-8mw2-4r3x ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- CVE-2026-96747 ↗
NIST National Vulnerability Database · official catalog
Observed . This product uses data from the NVD API but is not endorsed or certified by the NVD.
- CVE-2026-96747 ↗
FIRST EPSS · official catalog
Observed . FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 3 ·
Source facts changed; compare the preserved prior revision.
- Revision 2 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.