Описание
Zeroconf is a pure Python implementation of multicast DNS service discovery. Prior to 0.149.5, DNSIncoming._decode_labels_at_offset recurses once per DNS-name compression pointer, and a single mDNS packet carrying chained pointers can trigger a RecursionError that escapes DNSIncoming.init, causing sustained CPU burn, log flooding, and degraded mDNS-dependent features for unauthenticated hosts on the local link over UDP/5353 (224.0.0.251 / ff02::fb). This issue is fixed in version 0.149.5.
A flaw was found in Zeroconf, a Python implementation of multicast DNS service discovery. An unauthenticated attacker on the local network can send a specially crafted multicast DNS (mDNS) packet with chained pointers. This can trigger a recursion error, leading to sustained CPU usage, excessive logging, and degraded mDNS services, ultimately causing a Denial of Service.
Отчет
Zeroconf is a pure Python implementation of multicast DNS (mDNS) service discovery. Prior to 0.149.5, a single mDNS packet carrying chained DNS-name compression pointers can trigger unbounded recursion in the label decoder, raising a RecursionError that escapes the packet parser and causes sustained CPU burn and log flooding, resulting in denial of service impact for unauthenticated hosts on the local network segment (UDP/5353, 224.0.0.251 / ff02::fb). Exploitation requires the attacker to be on the same local link as the affected host, consistent with Red Hat's Adjacent (AV:A) attack vector scoring. This issue is fixed upstream in zeroconf 0.149.5. Red Hat's CVSS score matches the vendor/CVE.org assessment for this flaw. This flaw is one of a batch of related Zeroconf issues discovered and fixed close together (CVE-2026-47180, CVE-2026-47183, CVE-2026-47184, CVE-2026-48045, CVE-2026-48487); all affect the same Red Hat product streams in the same way and were triaged consistently as a batch.
Меры по смягчению последствий
Upgrade to zeroconf 0.149.5 or later once packaged in the affected Red Hat product. Where upgrading isn't immediately possible, restricting the affected host's exposure to the local network segment (network segmentation or firewalling multicast DNS traffic on UDP/5353) reduces the practical attack surface, since exploitation requires local-link access.
Ссылки на источники
Дополнительная информация
Статус:
EPSS
6.5 Medium
CVSS3
Связанные уязвимости
Zeroconf is a pure Python implementation of multicast DNS service discovery. Prior to 0.149.5, DNSIncoming._decode_labels_at_offset recurses once per DNS-name compression pointer, and a single mDNS packet carrying chained pointers can trigger a RecursionError that escapes DNSIncoming.__init__, causing sustained CPU burn, log flooding, and degraded mDNS-dependent features for unauthenticated hosts on the local link over UDP/5353 (224.0.0.251 / ff02::fb). This issue is fixed in version 0.149.5.
Zeroconf is a pure Python implementation of multicast DNS service discovery. Prior to 0.149.5, DNSIncoming._decode_labels_at_offset recurses once per DNS-name compression pointer, and a single mDNS packet carrying chained pointers can trigger a RecursionError that escapes DNSIncoming.__init__, causing sustained CPU burn, log flooding, and degraded mDNS-dependent features for unauthenticated hosts on the local link over UDP/5353 (224.0.0.251 / ff02::fb). This issue is fixed in version 0.149.5.
Zeroconf is a pure Python implementation of multicast DNS service disc ...
zeroconf has unbounded recursion in DNS compression-pointer decoder that allows LAN-local denial of service
EPSS
6.5 Medium
CVSS3