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CVE-2022-2928

An option refcount overflow exists in dhcpd

Description

In ISC DHCP 4.4.0 -> 4.4.3, ISC DHCP 4.1-ESV-R1 -> 4.1-ESV-R16-P1, when the function option_code_hash_lookup() is called from add_option(), it increases the option's refcount field. However, there is not a corresponding call to option_dereference() to decrement the refcount field. The function add_option() is only used in server responses to lease query packets. Each lease query response calls this function for several options, so eventually, the reference counters could overflow and cause the server to abort.

Timeline

  1. ID reserved

    By isc

  2. · 46 days later

    Published

  3. · 24 months later

    Record updated

Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.

Scores

CVSS scores of CVE-2022-2928, by who scored it
Scored byCVSSScoreVector
iscCNA (assigner)3.1Medium6.5CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVDNVD · Modified3.1Medium6.5CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS (exploitation in 30 days)
0.71% · top 46% of all CVEs (11 Nov 2026)
Loading the EPSS history…

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.5.

Affected products

  • ISC · ISC DHCP

    • affected 4.4.0 through versions before 4.4.3-P1
    • affected 4.1 ESV 4.1-ESV-R1 through versions before 4.1-ESV-R16-P1

What to do

Solution: Upgrade to the patched release most closely related to your current version of ISC DHCP. These can all be downloaded from https://www.isc.org/downloads. 4.4.3-P1 4.1-ESV-R16-P2

Workaround: Disable lease query on the server for DHCPv4 or restart the server periodically.

Exploitation: We are not aware of any active exploits.

References

References6

Sources

The same CVE in the primary databases and aggregators, to check against.

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Record last updated .