CVE-2023-53873Public exploitNetwork attack vector

Unauthenticated service crash via oversized login password

Published Dec 15, 2025 · Updated Dec 15, 2025

Denial of service in SyncBreeze 15.2.24 allows remote attackers to crash the server through the web-management login endpoint. The /login handler consumes an oversized password value formed from 500 repeated password= strings without enforcing an effective input limit. No authentication or user interaction is required, but the web interface must be enabled and network-reachable; exploitation interrupts the SyncBreeze service.

CVSS severity8.7
High
EPSS probability0.49%
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 SyncBreeze 15.2.24 allows remote attackers to crash the server through the web-management login endpoint. The /login handler consumes an oversized password value formed from 500 repeated password= strings without enforcing an effective input limit. No authentication or user interaction is required, but the web interface must be enabled and network-reachable; exploitation interrupts the SyncBreeze service.

The record

CVE
CVE-2023-53873
Published
Dec 15, 2025
Updated
Dec 15, 2025
Vendor
Flexense Ltd.
Product
SyncBreeze
Classifications
CWE-400, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 15, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 15, 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=15.2.24

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Flexense Ltd. · SyncBreezeversion=15.2.24

Published CVSS scores

8.7VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

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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