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VulnerabilityPublished

CVE-2025-48053: discourse · Uncontrolled Resource Consumption

Affects discourseSource CVE Database V5

0

Not known to be exploited · CVSS 8.7 High : upgrade to 3.4.4 soon.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 4.0 base score
8.7High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 30% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 3.4.4
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

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 9 Jun 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade discourse/discourse to 3.4.4.

Affected software

ProductAffectedFixed in
GitHubdiscourse/discoursepkg:github/discourse/discourseOther threatsAffected
  • <3.4.4
Fixed in
  • 3.4.4

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

European organizations should prioritize updating Discourse instances to at least version 3.4.4 (stable), 3.5.0.beta5 (beta), or 3.5.0.beta6-dev (tests-passed) as soon as possible to apply the official patches. If you cannot patch yet, organizations should consider restricting or monitoring PMs sent to bot users, possibly implementing rate limiting or filtering mechanisms at the application or network level to detect and block suspicious URLs. Deploying Web Application Firewalls (WAFs) with custom rules to identify and block malformed or suspicious URL payloads targeting Discourse bots can provide an additional layer of defense. Regularly auditing Discourse logs for unusual PM activity and anomalous resource usage patterns can help detect attempted exploitation. Organizations should also review and harden bot user configurations to minimize exposure. Finally, maintaining an incident response plan that includes steps for mitigating denial of service incidents will improve resilience.

Description

Discourse is an open-source discussion platform. Prior to version 3.4.4 of the `stable` branch, version 3.5.0.beta5 of the `beta` branch, and version 3.5.0.beta6-dev of the `tests-passed` branch, sending a malicious URL in a PM to a bot user can cause a reduced the availability of a Discourse instance. This issue is patched in version 3.4.4 of the `stable` branch, version 3.5.0.beta5 of the `beta` branch, and version 3.5.0.beta6-dev of the `tests-passed` branch. No known workarounds are available.

References

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