CVE-2021-32832Public exploitNetwork attack vector

Authenticated service interruption via exponential regex backtracking

Published Aug 30, 2021 · Updated Aug 3, 2024

Regular expression denial of service in Rocket.Chat before 3.11.3 allows remote authenticated users to interrupt the service. Two patterns in mailer/server/api.js and CustomFieldsAdditionalForm.js use overlapping repeated groups, so crafted nonmatching text triggers exponential backtracking. An authenticated user must reach either input path; published research tested only the isolated expressions and did not reproduce full-service disruption.

CVSS severity4.3
Medium
EPSS probability1.62%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Regular expression denial of service in Rocket.Chat before 3.11.3 allows remote authenticated users to interrupt the service. Two patterns in mailer/server/api.js and CustomFieldsAdditionalForm.js use overlapping repeated groups, so crafted nonmatching text triggers exponential backtracking. An authenticated user must reach either input path; published research tested only the isolated expressions and did not reproduce full-service disruption.

The record

CVE
CVE-2021-32832
Published
Aug 30, 2021
Updated
Aug 3, 2024
Vendor
Rocket.Chat Technologies Corp.
Product
Rocket.Chat
Classifications
CWE-400, T1499.003
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 30, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 3.11.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Rocket.Chat Technologies Corp. · Rocket.Chatversion=< 3.11.3

Published CVSS scores

4.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499.003Application Exhaustion Flood

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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