CVE-2026-48497
MediumCVSS 5.9Exploitation Probability (EPSS)
Low risk29th percentile — higher than 29% of all known CVEs
Summary
In Envoy, when the UDP DNS filter is configured with local or remote resolution for a name of 255 octets, a query with such a name causes abnormal process termination. This is due to an invalid runtime precondition that the name must be strictly less than 255 octets, contradicting RFC 1035.
Risk Assessment
An attacker can intentionally send a DNS query with a 255-octet name, causing the Envoy proxy to crash and disrupting network services, leading to a denial of service (DoS).
Recommendation
Immediately upgrade Envoy to version 1.35.11, 1.36.7, 1.37.3, or 1.38.1, depending on your branch, to remediate this vulnerability.
Original NVD description (English source)
Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.35.11, 1.36.7, 1.37.3, and 1.38.1, in cases where UDP DNS filter is configured with local resolution containing a name with the length of 255 octets or remote resolution for a name of 255 octets long can complete successfully, a query with such name will result in abnormal process termination. The abnormal process termination is triggered by an invalid runtime precondition that the query name is strictly less than 255 octets, contradicting DNS specification rfc1035#section-2.3.4 that the name can be 255 or less octets. This vulnerability is fixed in 1.35.11, 1.36.7, 1.37.3, and 1.38.1.