CVE-2023-36461Network attack vector

Server hang via noncumulative HTTP read timeout

Published Jul 6, 2023 · Updated Feb 13, 2025

Denial of service in Mastodon before 3.5.9, 4.0.0 through 4.0.4, and 4.1.0 through 4.1.2 allows remote attackers to make instances unresponsive. HTTP::Timeout::PerOperation limits each socket read rather than the complete response, so a peer that repeatedly supplies partial data renews the wait indefinitely. A malicious federated server must answer Mastodon's outbound requests slowly; enough stalled requests occupy all workers and halt useful service.

CVSS severity7.5
High
EPSS probability1.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Mastodon before 3.5.9, 4.0.0 through 4.0.4, and 4.1.0 through 4.1.2 allows remote attackers to make instances unresponsive. HTTP::Timeout::PerOperation limits each socket read rather than the complete response, so a peer that repeatedly supplies partial data renews the wait indefinitely. A malicious federated server must answer Mastodon's outbound requests slowly; enough stalled requests occupy all workers and halt useful service.

The record

CVE
CVE-2023-36461
Published
Jul 6, 2023
Updated
Feb 13, 2025
Vendor
Mastodon
Product
Mastodon
Classifications
CWE-770, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 6, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 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=< 3.5.9
  2. Affected versionversion=>= 4.0.0, < 4.0.5
  3. Affected versionversion=>= 4.1.0, < 4.1.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mastodon · Mastodonversion=< 3.5.9; version=>= 4.0.0, < 4.0.5; version=>= 4.1.0, < 4.1.3

Published CVSS scores

7.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.004Application or System Exploitation

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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