CVE-2026-93761

Denial of service via unbounded regex matching in Mongoid's in-memory query matcher

Published Sep 18, 2026 CVSS 4.0 · 8.7 High EPSS < 1% KEV · Not listed

Description

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.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

MongoDB Inc.

Mongoid

unaffected

Version	Status	Constraints
`7.2.0`	affected	≤ 7.2.6
`7.3.0`	affected	≤ 7.3.5
`7.4.0`	affected	≤ 7.4.3
`7.5.0`	affected	≤ 7.5.4
`7.6.0`	affected	≤ 7.6.1
`8.0.0`	affected	≤ 8.0.12
`8.1.0`	affected	≤ 8.1.12
`9.0.0`	affected	≤ 9.0.11
`9.1.0`	affected	—

Configuration 1 [-]

OR	cpe:2.3:a:mongodb:mongoid::::::::
	cpe:2.3:a:mongodb:mongoid::::::::
	cpe:2.3:a:mongodb:mongoid::::::::
	cpe:2.3:a:mongodb:mongoid:9.1.0:::::::*

No data.

Vendor Product Versions

Mongodb

Mongoid

Version	Status	Scheme	Platform
`[7.2.0,7.2.6]`	affected	semver	—
`[7.3.0,7.3.5]`	affected	semver	—
`[7.4.0,7.4.3]`	affected	semver	—
`[7.5.0,7.5.4]`	affected	semver	—
`[7.6.0,7.6.1]`	affected	semver	—
`[8.0.0,8.0.12]`	affected	semver	—
`[8.1.0,8.1.12]`	affected	semver	—
`[9.0.0,9.0.11]`	affected	semver	—
`9.1.0`	affected	semver	—

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

No advisories available

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.460% probability within 30 days)

Exploitation none

Automatable yes

Technical Impact partial

References

Link	Providers
https://jira.mongodb.org/browse/MONGOID-5981

History

Sep 24, 2026 4:15 PM Affected versions updated View changes

Type	Values Removed	Values Added
CPEs		cpe:2.3:a:mongodb:mongoid:::::::: cpe:2.3:a:mongodb:mongoid:9.1.0:::::::*

Sep 21, 2026 7:45 PM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Mongodb Mongodb mongoid
Vendors & Products		Mongodb Mongodb mongoid

Sep 19, 2026 3:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Sep 18, 2026 9:30 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		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.
Title		Denial of service via unbounded regex matching in Mongoid's in-memory query matcher
Weaknesses		CWE-1333
References		https://jira.mongodb.org/browse/MONGOID-5981
Metrics		cvssV3_1 `{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}` cvssV4_0 `{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}`