CVE-2026-93765: Mongoid contains an unsafe reflection weakness in the document persistence layer of its object-document mappin

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CRITICAL 9.1REMOTEUPGRADE

CVE-2026-93765 is a critical-severity flaw (CVSS 9.1) affecting mongoid. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Mongoid contains an unsafe reflection weakness in the document persistence layer of its object-document mapping code. Input whose keys are passed through from an unauthenticated party by an embedding application can cause unintended internal method invocation instead of the intended array field update. This may result in unintended removal of stored records and in the embedding application becoming unresponsive.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 57%)
CISA exploited list	No
Weakness	CWE-470
Published	2026-09-18
Last modified	2026-09-25

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

Last updated 2026-09-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-09-18 17:17 UTCPublished CVE record published
2026-09-25 14:10 UTCUpdated Record last modified

mongodb mongoid UPGRADE

Affected: >= 8.0.0 and < 8.0.12 · >= 8.1.0 and < 8.1.13 · >= 9.0.0 and < 9.0.12 · 9.1.0

Fixed in: 8.0.12, 8.1.13, 9.0.12

Safe to downgrade to: a release before 8.0.0

1. Check installed version

apt-cache policy mongoid || rpm -q mongoid || mongoid --version

2. UPGRADE to 8.0.12 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade mongoid

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade mongoid

Note

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

3. If no update is available yet, DOWNGRADE to a release before 8.0.0 (Debian / Ubuntu)

apt-cache madison mongoid sudo apt install mongoid=<VERSION_BEFORE_8.0.0> sudo apt-mark hold mongoid

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list mongoid sudo dnf downgrade mongoid-<VERSION_BEFORE_8.0.0> sudo dnf versionlock add mongoid

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2026-93765?

mongoid: upgrade to 8.0.12, 8.1.13, 9.0.12. Exact commands for each OS are on this page.

Is CVE-2026-93765 being exploited?

CVE-2026-93765 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-2026-93765 affect?

CVE-2026-93765 affects mongoid. Severity is critical (CVSS 9.1). Mongoid contains an unsafe reflection weakness in the document persistence layer of its object-document mapping code. Input whose keys are passed through from an unauthenticated party by an embedding application can cause unintended interna

How urgent is CVE-2026-93765?

Priority 48/100. Critical severity; Remotely exploitable, no login, no user action

Software pages

MongoDB vulnerabilities

Related CVEs

CVE-2026-93758 HIGH 8.1 UPGRADE An insecure direct object reference in the nested attributes handling of the Mongoid object-document mapper ma
CVE-2026-93759 HIGH 8.6 UPGRADE Mongoid does not neutralize a string-typed query criterion supplied to its query builder, and instead passes i
CVE-2026-93760 HIGH 8.2 UPGRADE Mongoid does not restrict which query operators may come from caller-supplied filter data when an application
CVE-2026-93761 HIGH 7.5 UPGRADE An inefficient regular expression complexity issue in the in-memory query evaluation component of the Mongoid
CVE-2026-93762 CRITICAL 9.8 UPGRADE Mongoid contains an unsafe reflection weakness in the query path used for embedded documents

References

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