Nixpkgs security tracker

Untriaged

Permalink CVE-2026-47778

4.4 MEDIUM

CVSS version (CVSS): 3.1
Attack Vector (AV): Network (N)
Attack Complexity (AC): High (H)
Privileges Required (PR): High (H)
User Interaction (UI): None (N)
Scope (S): Unchanged (U)
Confidentiality (C): High (H)
Integrity (I): None (N)
Availability (A): None (N)
Modified Attack Vector (MAV): Network (N)
Modified Attack Complexity (MAC): High (H)
Modified Privileges Required (MPR): High (H)
Modified User Interaction (MUI): None (N)
Modified Confidentiality (MC): High (H)
Modified Scope (MS): Unchanged (U)
Modified Integrity (MI): None (N)
Modified Availability (MA): None (N)

created 2 months ago Activity log

Created suggestion 2 months ago

Envoy: Embedded NUL in TLS DNS SAN Truncation in the Default TLS Certificate Validator. (Auth Bypass)

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, a structural flaw was identified in DefaultCertValidator::verifySubjectAltName where the extracted DNS SAN string is cast to a C-style string using .c_str() before being passed to the Utility::dnsNameMatch() algorithm. If the attacker serves a certificate with a dNSName SAN containing an embedded NUL byte, the helper Utility::generalNameAsString captures the complete string including the NUL. However, when .c_str() evaluates it, implicit conversion to absl::string_view inside dnsNameMatch relies on strlen(), prematurely truncating the evaluation context. Envoy evaluates trucated string against the exact required config_san match and returns true, thereby successfully validating the string with the Nul byte for an upstream routing. This vulnerability is fixed in 1.35.11, 1.36.7, 1.37.3, and 1.38.1.