CVE-2023-40296Public exploitNetwork attack vector

UDP server crash via off-by-one null terminator

Published Aug 14, 2023 · Updated Oct 9, 2024

Stack-based buffer overflow in async-sockets-cpp 0.3.1 and earlier allows remote attackers to crash UDP servers with malformed packets. ReceiveFrom passes the stack-buffer size to recvfrom, then writes a null terminator at tempBuffer[messageLength], one byte beyond the buffer when a datagram fills it. Any unauthenticated sender that can reach an affected UDP server can terminate its receiving thread or process, interrupting service.

CVSS severity7.5
High
EPSS probability0.89%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Stack-based buffer overflow in async-sockets-cpp 0.3.1 and earlier allows remote attackers to crash UDP servers with malformed packets. ReceiveFrom passes the stack-buffer size to recvfrom, then writes a null terminator at tempBuffer[messageLength], one byte beyond the buffer when a datagram fills it. Any unauthenticated sender that can reach an affected UDP server can terminate its receiving thread or process, interrupting service.

The record

CVE
CVE-2023-40296
Published
Aug 14, 2023
Updated
Oct 9, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 14, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 9, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

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

7.5NIST NVDCVSS: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.

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-787Out-of-bounds Write
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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo