CVE-2025-23016Public exploit

Code execution via wrapped parameter allocation

Published Jan 10, 2025 · Updated Feb 26, 2026

Heap-based buffer overflow in FastCGI Developer's Kit 2.0.0 through 2.4.4 allows attackers to execute code via crafted IPC data. On 32-bit builds, ReadParams adds attacker-controlled nameLen and valueLen with two extra bytes, wraps the allocation size, then copies the declared data into the undersized heap buffer. Access normally requires the local FastCGI socket; a network path exists only when that socket is exposed or reachable through SSRF, and successful corruption can crash the process or redirect execution.

CVSS severity9.3
Critical
EPSS probability0.58%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in FastCGI Developer's Kit 2.0.0 through 2.4.4 allows attackers to execute code via crafted IPC data. On 32-bit builds, ReadParams adds attacker-controlled nameLen and valueLen with two extra bytes, wraps the allocation size, then copies the declared data into the undersized heap buffer. Access normally requires the local FastCGI socket; a network path exists only when that socket is exposed or reachable through SSRF, and successful corruption can crash the process or redirect execution.

The record

CVE
CVE-2025-23016
Published
Jan 10, 2025
Updated
Feb 26, 2026
Vendor
FastCGI
Product
FastCGI Developer's Kit
Classifications
CWE-190
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 10, 2025CVE publishedPublication date reported by the CVE source.
  2. Feb 26, 2026Record 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=2.0.0 <=2.4.4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

FastCGI · FastCGI Developer's Kitversion=2.0.0 <=2.4.4

Published CVSS scores

9.3MITRECVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-190Integer Overflow or Wraparound

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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