CVE-2026-106436 Application denial of service and data truncation via unchecked BSON append failures in MongoDB PHP Driver
An unauthenticated attacker can cause denial of service or data truncation in applications using the MongoDB PHP Driver by triggering unchecked BSON append failures.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-106436?
CVE-2026-106436 is a medium-severity denial of service vulnerability in MongoDB PHP Driver, published on 8 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
The BSON encoder in the MongoDB PHP Driver does not check some return values after a document exceeds libbson's size limit. This can leave the encoder in an invalid state. An unauthenticated actor who can cause an affected application to encode an unusually large data structure can terminate the PHP worker or cause the resulting document to omit fields. No MongoDB server connection or database authentication is required.
Weakness: CWE-252
Which versions are affected by CVE-2026-106436?
It affects 1 product.
Products include Mongodb Php Driver.
How do I fix CVE-2026-106436?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-106436 being exploited?
There is no known exploitation of CVE-2026-106436 in the wild and no public exploit code.
Other vulnerabilities in MongoDB PHP Driver
- CVE-2026-81525 Cross-tenant database retargeting via dot/NUL injection in namespace strings in the PHP Driver
- CVE-2026-84968 Heap out-of-bounds read via corrupt nested BSON in field path error message
- CVE-2026-6811 PHP Stack Exhaustion
- CVE-2026-106432 Heap buffer overflow via 32-bit string-length truncation in MongoDB PHP Driver
Sources
Also known as DEBIAN-CVE-2026-106436, UBUNTU-CVE-2026-106436.