CVE-2022-2928

Server abort via lease-query reference-count overflow

Published Oct 7, 2022 · Updated Sep 17, 2024

Denial of service in ISC DHCP 4.4.0 through 4.4.3 allows remote attackers to abort dhcpd via repeated lease queries. The add_option() response path calls option_code_hash_lookup(), which increments each option's refcount without a matching option_dereference(). The 4.1 ESV branch is also affected; exploitation requires network access and allow leasequery configuration, and counter exhaustion crashes only the server process.

CVSS severity6.5
Medium
EPSS probability0.69%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in ISC DHCP 4.4.0 through 4.4.3 allows remote attackers to abort dhcpd via repeated lease queries. The add_option() response path calls option_code_hash_lookup(), which increments each option's refcount without a matching option_dereference(). The 4.1 ESV branch is also affected; exploitation requires network access and allow leasequery configuration, and counter exhaustion crashes only the server process.

The record

CVE
CVE-2022-2928
Published
Oct 7, 2022
Updated
Sep 17, 2024
Vendor
Internet Systems Consortium
Product
ISC DHCP
Classifications
CWE-476, T1499.004
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 7, 2022CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record 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=4.1 ESV 4.1-ESV-R1 through versions before 4.1-ESV-R16-P1
  2. Affected versionversion=4.4.0 through versions before 4.4.3-P1

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Internet Systems Consortium · ISC DHCPversion=4.1 ESV 4.1-ESV-R1 through versions before 4.1-ESV-R16-P1; version=4.4.0 through versions before 4.4.3-P1

Published CVSS scores

6.5Internet Systems ConsortiumCVSS:3.1/AV:A/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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