CVE-2020-12135

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.2% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2020-04-24 · updated 2026-06-17
Weakness: CWE-190

Description

bson before 0.8 incorrectly uses int rather than size_t for many variables, parameters, and return values. In particular, the bson_ensure_space() parameter bytesNeeded could have an integer overflow via properly constructed bson input.

Affected products

MongoDB C# Driver: before 0.8 — fixed in 0.8
Whoopsie Project Whoopsie: through 0.2.69

How to fix

Upgrade to a fixed version: MongoDB C# Driver 0.8. Check the vendor advisory for mitigations.

References

https://bugs.launchpad.net/ubuntu/+source/whoopsie/+bug/1872560
https://github.com/10gen-archive/mongo-c-driver-legacy/commit/1a1f5e26a4309480d88598913f9eebf9e9cba8ca#diff-f7d29a680148f52d6601f59ed787f577
https://launchpadlibrarian.net/474887364/bson-fix-overflow.patch
https://usn.ubuntu.com/4450-1/
https://bugs.launchpad.net/ubuntu/+source/whoopsie/+bug/1872560
https://github.com/10gen-archive/mongo-c-driver-legacy/commit/1a1f5e26a4309480d88598913f9eebf9e9cba8ca#diff-f7d29a680148f52d6601f59ed787f577
https://launchpadlibrarian.net/474887364/bson-fix-overflow.patch
https://usn.ubuntu.com/4450-1/

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