CVE-2020-15853Public exploitNetwork attack vector

IRC service interruption via unrestricted refresh command

Published Oct 18, 2022 · Updated May 13, 2025

Resource-consumption flaw in Fedora Project supybot-fedora all versions allows remote attackers to interrupt IRC bot service. The unrestricted refresh command rebuilds the cache from every Fedora Account System user without an owner-only authorization check, leaving zodbot unresponsive for about 20 to 30 minutes. Any IRC user able to send the command can cause the interruption; no data access, modification, crash, or persistent outage is reported.

CVSS severity5.3
Medium
EPSS probability0.64%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource-consumption flaw in Fedora Project supybot-fedora all versions allows remote attackers to interrupt IRC bot service. The unrestricted refresh command rebuilds the cache from every Fedora Account System user without an owner-only authorization check, leaving zodbot unresponsive for about 20 to 30 minutes. Any IRC user able to send the command can cause the interruption; no data access, modification, crash, or persistent outage is reported.

The record

CVE
CVE-2020-15853
Published
Oct 18, 2022
Updated
May 13, 2025
Vendor
Fedora Project
Product
supybot-fedora
Classifications
CWE-400, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 18, 2022CVE publishedPublication date reported by the CVE source.
  2. May 13, 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=all versions

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Fedora Project · supybot-fedoraversion=all versions

Published CVSS scores

5.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

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.

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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 exploitPublished

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499Endpoint Denial of Service

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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