CVE-2025-51495Public exploitNetwork attack vector

Remote crash via WebSocket offset underflow

Published Sep 29, 2025 · Updated Sep 29, 2025

Integer overflow in Cesanta Mongoose 7.5 through 7.17 allows remote attackers to crash WebSocket-enabled applications. The mg_ws_cb handler subtracts one from a zero size_t frame offset and exposes the wrapped length to subsequent WebSocket processing. A remotely reachable Mongoose WebSocket handler is required; an application crash is demonstrated, while memory corruption depends on downstream integration.

CVSS severity7.5
High
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

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Summary

What happened

Integer overflow in Cesanta Mongoose 7.5 through 7.17 allows remote attackers to crash WebSocket-enabled applications. The mg_ws_cb handler subtracts one from a zero size_t frame offset and exposes the wrapped length to subsequent WebSocket processing. A remotely reachable Mongoose WebSocket handler is required; an application crash is demonstrated, while memory corruption depends on downstream integration.

The record

CVE
CVE-2025-51495
Published
Sep 29, 2025
Updated
Sep 29, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-190, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 29, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 29, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5CISA-ADPCVSS: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-190Integer Overflow or Wraparound
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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