CVE-2026-93761: An inefficient regular expression complexity issue in the in-memory query evaluation component of the Mongoid

This month

HIGH 7.5REMOTEUPGRADE

CVE-2026-93761 is a high-severity flaw (CVSS 7.5) affecting mongoid. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An inefficient regular expression complexity issue in the in-memory query evaluation component of the Mongoid library may allow an unauthenticated party to cause excessive processing within an embedding application process. Applications that place user-supplied text into a pattern-matching query condition on an embedded association may become unresponsive.

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 60%)
CISA exploited list	No
Weakness	CWE-1333
Published	2026-09-18
Last modified	2026-09-24

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

Last updated 2026-09-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-09-18 18:18 UTCPublished CVE record published
2026-09-24 16:06 UTCUpdated Record last modified

mongodb mongoid UPGRADE

Affected: >= 8.0.0 and < 8.0.13 · >= 8.1.0 and < 8.1.13 · >= 9.0.0 and < 9.0.12 · 9.1.0

Fixed in: 8.0.13, 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 8.0.13 (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-2026-93761?

mongoid: upgrade to 8.0.13, 8.1.13, 9.0.12. Exact commands for each OS are on this page.

Is CVE-2026-93761 being exploited?

CVE-2026-93761 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-2026-93761 affect?

CVE-2026-93761 affects mongoid. Severity is high (CVSS 7.5). An inefficient regular expression complexity issue in the in-memory query evaluation component of the Mongoid library may allow an unauthenticated party to cause excessive processing within an embedding application process. Applications tha

How urgent is CVE-2026-93761?

Priority 41/100. High 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-2026-93765 CRITICAL 9.1 UPGRADE Mongoid contains an unsafe reflection weakness in the document persistence layer of its object-document mappin
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-2026-93762 CRITICAL 9.8 UPGRADE Mongoid contains an unsafe reflection weakness in the query path used for embedded documents

References

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