CoreDNS: proxyproto plugin panics on PPv2 datagram with non-UDP transport — single 28-byte packet remote DoS
Description
A vulnerability in CoreDNS's proxyproto plugin causes a panic when processing a Proxy Protocol version 2 datagram with a non-UDP transport, resulting in a remote denial of service triggered by a single 28-byte packet. This affects CoreDNS version 3.0. No CVSS score is available for this issue.
Affected software
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The CoreDNS proxyproto plugin improperly handles Proxy Protocol version 2 datagrams that specify a transport protocol other than UDP. When such a datagram is received, the plugin panics, causing the CoreDNS service to crash. This vulnerability can be exploited remotely by sending a specially crafted 28-byte packet, leading to a denial of service condition. The issue is identified as CWE-476 (NULL Pointer Dereference). The affected version is CoreDNS 3.0.
Potential Impact
An attacker can remotely cause the CoreDNS service to crash by sending a single crafted packet, resulting in a denial of service. This disrupts DNS resolution services relying on the affected CoreDNS instance until it is restarted or recovered.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, consider implementing network-level filtering to block malformed Proxy Protocol v2 packets with non-UDP transport or restrict access to the CoreDNS proxyproto plugin to trusted sources only.
Technical Details
- Gcve Source
- db.gcve.eu
- Csaf Category
- csaf_vex
- Csaf Version
- 2.0
- Publisher
- Microsoft Security Response Center
- Advisory Id
- msrc_CVE-2026-62309
- Cve Count
- 1
Threat ID: 6a5b60912d1edb114c84a461
Added to database: 07/18/2026, 11:16:33 UTC
Last enriched: 09/16/2026, 23:21:02 UTC
Last updated: 10/14/2026, 06:48:19 UTC
Views: 124
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