CVE-2022-24824Network attack vector

Anonymous-user denial of service via incomplete cache key

Published Apr 14, 2022 · Updated Apr 23, 2025

Cache poisoning in Discourse's anonymous-cache middleware before 2.8.3 and before 2.9.0.beta4 allows remote attackers to disrupt page rendering. The cache key omits the CrawlerDetection.show_browser_update? result derived from the User-Agent header, so an old-browser response can be reused for other anonymous requests. No authentication is required; successful poisoning serves the crawler view instead of the normal HTML page, causing partial service interruption for anonymous visitors.

CVSS severity5.3
Medium
EPSS probability1.02%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cache poisoning in Discourse's anonymous-cache middleware before 2.8.3 and before 2.9.0.beta4 allows remote attackers to disrupt page rendering. The cache key omits the CrawlerDetection.show_browser_update? result derived from the User-Agent header, so an old-browser response can be reused for other anonymous requests. No authentication is required; successful poisoning serves the crawler view instead of the normal HTML page, causing partial service interruption for anonymous visitors.

The record

CVE
CVE-2022-24824
Published
Apr 14, 2022
Updated
Apr 23, 2025
Vendor
Discourse
Product
Discourse
Classifications
CWE-829, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 14, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 23, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=< 2.8.3
  2. Affected versionversion=< 2.9.0.beta4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Discourse · Discourseversion=< 2.8.3; version=< 2.9.0.beta4

Published CVSS scores

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

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-829Inclusion of Functionality from Untrusted Control Sphere
T1499Endpoint Denial of Service

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

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Your stack

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