Vulnerability · Published Oct 8, 2026 · Assigned by mongodb
CVE-2026-106435Application denial of service via out-of-bounds read in BSON Regex decoding in MongoDB Python Driver
Medium 5.1
In plain English
A medium-severity out-of-bounds read in Python Driver from MongoDB. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 1% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
The MongoDB Python Driver's binary accelerator can read outside a buffer when an application decodes malformed BSON containing a truncated regular-expression element without a trailing NUL byte. An actor who can supply BSON to the documented decode or decode_all API can cause the application process to terminate when the C extension is loaded. The driver's normal database wire-protocol path does not reach this code.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | pymongo | no fix listed | DEBIAN-CVE-2026-106435 |
| Debian:13 | pymongo | no fix listed | DEBIAN-CVE-2026-106435 |
| Debian:14 | pymongo | 4.19.0-1 | DEBIAN-CVE-2026-106435 |
| PyPI | pymongo | 4.18.3 | GHSA-98qm-wvgf-w4cf |
| Ubuntu:22.04:LTS | pymongo | no fix listed | UBUNTU-CVE-2026-106435 |
| Ubuntu:24.04:LTS | pymongo | no fix listed | UBUNTU-CVE-2026-106435 |
| Ubuntu:26.04:LTS | pymongo | no fix listed | UBUNTU-CVE-2026-106435 |
| Ubuntu:26.10 | pymongo | no fix listed | UBUNTU-CVE-2026-106435 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| MongoDB | Python Driver | 0.10.3 – through 4.18.2 |
Weakness: CWE-125 · Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H