CVE-2023-49441Public exploitNetwork attack vector

Undefined behavior via signed SHA-256 left shift

Published Jun 6, 2024 · Updated Mar 14, 2025

Undefined behavior in dnsmasq 2.9 allows remote attackers to trigger a signed integer overflow by sending a crafted DNS query. The built-in SHA-256 transform shifts a byte promoted to signed int by 24 bits while forward_query hashes the question, which UBSan flags as unrepresentable. The path requires dnsmasq's built-in hash implementation; the developer states that any wrong hash is compared with another calculated identically, leaving no practical security impact.

CVSS severity7.5
High
EPSS probability0.66%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Undefined behavior in dnsmasq 2.9 allows remote attackers to trigger a signed integer overflow by sending a crafted DNS query. The built-in SHA-256 transform shifts a byte promoted to signed int by 24 bits while forward_query hashes the question, which UBSan flags as unrepresentable. The path requires dnsmasq's built-in hash implementation; the developer states that any wrong hash is compared with another calculated identically, leaving no practical security impact.

The record

CVE
CVE-2023-49441
Published
Jun 6, 2024
Updated
Mar 14, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 6, 2024CVE publishedPublication date reported by the CVE source.
  2. Mar 14, 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
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-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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