CVE-2026-106435: The MongoDB Python Driver's binary accelerator can read outside a buffer when an application decodes malformed

Q: How do I fix CVE-2026-106435?

python driver: upgrade to 4.18.3. Exact commands for each OS are on this page.

Q: Is CVE-2026-106435 being exploited?

CVE-2026-106435 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-106435 affect?

CVE-2026-106435 affects python driver. Severity is medium (CVSS 5.1). 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 documente

Q: How urgent is CVE-2026-106435?

Priority 18/100. No elevated risk signals yet.

Routine

MEDIUM 5.1UPGRADE

CVE-2026-106435 is a medium-severity flaw (CVSS 5.1) affecting python driver. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.1 (Medium)
Attack vector	Local
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.1% (top 99%)
CISA exploited list	No
Weakness	CWE-125
Published	2026-10-08
Last modified	2026-10-15

Publisher (CNA): MongoDB, Inc. · Vendor: mongodb

Last updated 2026-10-15 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-10-08 21:17 UTCPublished CVE record published
2026-10-15 17:00 UTCUpdated Record last modified

mongodb python driver UPGRADE

Affected: < 4.18.3

Fixed in: 4.18.3

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy python-driver || rpm -q python-driver || python-driver --version

2. UPGRADE to 4.18.3 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade python-driver

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade python-driver

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-106435?

python driver: upgrade to 4.18.3. Exact commands for each OS are on this page.

Is CVE-2026-106435 being exploited?

CVE-2026-106435 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-106435 affect?

CVE-2026-106435 affects python driver. Severity is medium (CVSS 5.1). 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 documente

How urgent is CVE-2026-106435?

Priority 18/100. No elevated risk signals yet.

Software pages

Python vulnerabilities · MongoDB vulnerabilities

References

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