CVE-2025-27421Public exploitNetwork attack vector

SSE denial of service via blocked cleanup channels

Published Mar 3, 2025 · Updated Mar 3, 2025

Resource exhaustion in Abacus before 1.4.0 allows remote attackers to disable SSE streaming by repeatedly disconnecting from /stream. The /stream event handler fails to remove disconnected clients and leaves cleanup channel operations blocked, so their goroutines remain alive indefinitely. No authentication or user interaction is required; sustained connection churn eventually makes only the SSE endpoint unresponsive while other API endpoints continue operating.

CVSS severity7.5
High
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in Abacus before 1.4.0 allows remote attackers to disable SSE streaming by repeatedly disconnecting from /stream. The /stream event handler fails to remove disconnected clients and leaves cleanup channel operations blocked, so their goroutines remain alive indefinitely. No authentication or user interaction is required; sustained connection churn eventually makes only the SSE endpoint unresponsive while other API endpoints continue operating.

The record

CVE
CVE-2025-27421
Published
Mar 3, 2025
Updated
Mar 3, 2025
Vendor
Abacus Research AG
Product
Abacus
Classifications
CWE-400, CWE-772, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 3, 2025CVE publishedPublication date reported by the CVE source.
  2. Mar 3, 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=< 1.4.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Abacus Research AG · Abacusversion=< 1.4.0

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.

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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
CWE-772Missing Release of Resource after Effective Lifetime
T1499.004Application or System Exploitation

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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