CVE-2026-9100 Heap memory out of bounds read and crash in C Driver legacy GridFS file reader
Attackers can crash applications or leak memory by providing malformed GridFS metadata to the MongoDB C Driver legacy API.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-9100?
CVE-2026-9100 is a medium-severity memory corruption vulnerability in MongoDB, Inc. C Driver, published on 20 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
The MongoDB C Driver's legacy GridFS API accepts malformed file metadata from the database without adequate validation. Crafted documents in a GridFS collection may cause any application that reads those files via the legacy API to either crash (via a division-by-zero) or silently leak process memory contents (via an out-of-bounds read).
Weakness: CWE-1285
Which versions are affected by CVE-2026-9100?
It affects 1 product.
Products include Mongodb C Driver.
How do I fix CVE-2026-9100?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-9100 being exploited?
There is no known exploitation of CVE-2026-9100 in the wild and no public exploit code.
Other vulnerabilities in MongoDB, Inc. C Driver
- CVE-2026-93393 Heap overflow via oversized decrypted TLS record sequence in Windows Secure Channel stream
- CVE-2026-6691 MongoDB C Driver Cyrus SASL Canonicalization Buffer Overflow
- CVE-2026-84964 Heap corruption via OCSP request double free from crafted multi-URL certificate in TLS client
- CVE-2024-7553 Accessing Untrusted Directory May Allow Local Privilege Escalation
- CVE-2026-93395 Integer Underflow → Heap Out-of-Bounds Read in `bson_new_from_buffer()
Sources
Also known as DEBIAN-CVE-2026-9100, GHSA-87jr-c2qj-3qrg, UBUNTU-CVE-2026-9100.