CVE-2025-34165Public exploitNetwork attack vector

Crash and memory disclosure via oversized broadcast payload

Published Aug 29, 2025 · Updated May 14, 2026

Stack-based out-of-bounds read in NetSupport Manager 14.x before 14.12.0000 allows remote attackers to crash the Windows Client or read memory. The BC_TCP_DATA handler trusts its payload-size field and copies beyond the 0x800-byte stack RX buffer into a broadcast slot. The Client listens on TCP port 5405, and unauthenticated broadcast commands expose adjacent stack memory; the flaw alone supports a crash or limited disclosure.

CVSS severity8.8
High
EPSS probability0.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based out-of-bounds read in NetSupport Manager 14.x before 14.12.0000 allows remote attackers to crash the Windows Client or read memory. The BC_TCP_DATA handler trusts its payload-size field and copies beyond the 0x800-byte stack RX buffer into a broadcast slot. The Client listens on TCP port 5405, and unauthenticated broadcast commands expose adjacent stack memory; the flaw alone supports a crash or limited disclosure.

The record

CVE
CVE-2025-34165
Published
Aug 29, 2025
Updated
May 14, 2026
Vendor
NetSupport Ltd.
Product
NetSupport Manager
Classifications
CWE-121, CAPEC-100, T1210, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 29, 2025CVE publishedPublication date reported by the CVE source.
  2. May 14, 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=14.0 <14.12.0000

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

NetSupport Ltd. · NetSupport Managerversion=14.0 <14.12.0000

Published CVSS scores

8.8VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/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.

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 exploitPublished

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
CAPEC-100Overflow Buffers
T1210Exploitation of Remote Services
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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