CVE-2021-37693Network attack vector

Account takeover via undeleted email verification tokens

Published Aug 13, 2021 · Updated Aug 4, 2024

Weak token invalidation in Discourse before 2.7.8 and beta builds before 2.8.0.beta4 allows remote attackers to reset account passwords. EmailChangeRequest lacks dependent destruction for old_email_token and new_email_token, so deleting the request leaves its associated EmailToken valid. An attack requires an unused verification token from an added email address and deletion of that address; reuse grants control of the affected account.

CVSS severity5.3
Medium
EPSS probability0.83%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Weak token invalidation in Discourse before 2.7.8 and beta builds before 2.8.0.beta4 allows remote attackers to reset account passwords. EmailChangeRequest lacks dependent destruction for old_email_token and new_email_token, so deleting the request leaves its associated EmailToken valid. An attack requires an unused verification token from an added email address and deletion of that address; reuse grants control of the affected account.

The record

CVE
CVE-2021-37693
Published
Aug 13, 2021
Updated
Aug 4, 2024
Vendor
Discourse
Product
Discourse
Classifications
CWE-640, CWE-613, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 13, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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=< 2.7.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Discourse · Discourseversion=< 2.7.8

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:P/A:N
5.3GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-640Weak Password Recovery Mechanism for Forgotten Password
CWE-613Insufficient Session Expiration
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo