Out-of-bounds read in mongo-python-driver - CVE-2026-106435
Published: October 15, 2026
Vulnerability identifier: #VU155866
CSH Severity: Medium
CVSS v4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-106435
CWE-ID: CWE-125
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to an out-of-bounds read in the C extension's BSON decoder when decoding malformed Regex elements. A remote attacker can supply a BSON document containing a truncated Regex element to cause a denial of service.
Exploitation requires the C extension to be loaded and untrusted BSON to be decoded from buffers without a NUL sentinel, such as mmap or array buffers accepted by bson.decode and bson.decode_all. The driver's own transport and pure-Python installations are not affected.
Affected software
mongo-python-driver
How to mitigate CVE-2026-106435
Install security update from vendor's website.
mongo-python-driver - update to 4.18.3