Red Hat Security Advisory: dnsmasq security update

Fixed packages 5

Vulnerabilities 6

• High 8.4
  CVE-2026-4892

  CVE-2026-4892

  A heap-based out-of-bounds write vulnerability in the DHCPv6 implementation of dnsmasq allows local attackers to execute arbitrary code with root privileges via a crafted DHCPv6 packet.

  dnsmasq dnsmasq dnsmasq dnsmasq Debian Ubuntu Alpine Wolfi
  May 11, 2026
• High 7.5
  CVE-2026-4890

  CVE-2026-4890

  A Denial of Service (DoS) vulnerability in the DNSSEC validation of dnsmasq allows remote attackers to cause a denial of service via a crafted DNS packet.

  dnsmasq dnsmasq dnsmasq dnsmasq Debian Ubuntu Azure Linux Alpine Wolfi
  May 11, 2026
• High 7.3
  CVE-2026-2291 Public exploit

  CVE-2026-2291

  dnsmasqs extract_name() function can be abused to cause a heap buffer overflow, allowing an attacker to inject false DNS cache entries, which could result in DNS lookups to redirect to an attacker-controlled IP address, or to cause a DoS.

  dnsmasq dnsmasq dnsmasq dnsmasq Debian Ubuntu Azure Linux Alpine Wolfi
  May 11, 2026
• High 7.3
  CVE-2026-5172 Public exploit

  CVE-2026-5172

  A buffer overflow in dnsmasq’s extract_addresses() function allows an attacker to trigger a heap out-of-bounds read and crash by exploiting a malformed DNS response, enabling extract_name() to advance the pointer past the record’s end.

  dnsmasq dnsmasq dnsmasq dnsmasq Debian Ubuntu Azure Linux Alpine Wolfi
  May 11, 2026
• Medium 5.3
  CVE-2026-4891

  CVE-2026-4891

  A heap-based out-of-bounds read vulnerability in the DNSSEC validation of dnsmasq allows remote attackers to cause a denial of service via a crafted DNS packet.

  dnsmasq dnsmasq dnsmasq dnsmasq Debian Ubuntu Azure Linux Alpine Wolfi
  May 11, 2026
• Medium 5.3
  CVE-2026-4893 Public exploit

  CVE-2026-4893

  An information disclosure vulnerability in dnsmasq allows remote attackers to bypass source checks via a crafted DNS packet with RFC 7871 client subnet information.

  dnsmasq dnsmasq dnsmasq dnsmasq Debian Ubuntu Azure Linux Alpine Wolfi
  May 11, 2026

References

• article
  https://access.redhat.com/security/updates/classification/#important
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2439088
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2458516
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2458517
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2458518
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2458519
• report
  https://bugzilla.redhat.com/show_bug.cgi?id=2458521
• advisory
  https://security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_19158.json
• report
  https://access.redhat.com/security/cve/CVE-2026-2291
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-2291
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-2291
• report
  https://access.redhat.com/security/cve/CVE-2026-4890
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-4890
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-4890
• article
  https://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2026q2/018471.html
• report
  https://access.redhat.com/security/cve/CVE-2026-4891
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-4891
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-4891
• report
  https://access.redhat.com/security/cve/CVE-2026-4892
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-4892
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-4892
• report
  https://access.redhat.com/security/cve/CVE-2026-4893
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-4893
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-4893
• report
  https://access.redhat.com/security/cve/CVE-2026-5172
• advisory
  https://www.cve.org/CVERecord?id=CVE-2026-5172
• advisory
  https://nvd.nist.gov/vuln/detail/CVE-2026-5172