uTLS is a fork of crypto/tls, created to customize ClientHello for fingerprinting resistance while still using it for the handshake. In versions 1.6.7 and below, uTLS did not implement the TLS 1.3 downgrade protection mechanism specified in RFC 8446 Section 4.1.3 when using a uTLS ClientHello spec. This allowed an active network adversary to downgrade TLS 1.3 connections initiated by a uTLS client to a lower TLS version (e.g., TLS 1.2) by modifying the ClientHello message to exclude the SupportedVersions extension, causing the server to respond with a TLS 1.2 ServerHello (along with a downgrade canary in the ServerHello random field). Because uTLS did not check the downgrade canary in the ServerHello random field, clients would accept the downgraded connection without detecting the attack. This attack could also be used by an active network attacker to fingerprint uTLS connections. This issue has been fixed in version 1.7.0.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - uTLS is a fork of crypto/tls, created to customize ClientHello for fingerprinting resistance while still     using it for the handshake. In versions 1.6.7 and below, uTLS did not implement the TLS 1.3 downgrade     protection mechanism specified in RFC 8446 Section 4.1.3 when using a uTLS ClientHello spec. This allowed     an active network adversary to downgrade TLS 1.3 connections initiated by a uTLS client to a lower TLS     version (e.g., TLS 1.2) by modifying the ClientHello message to exclude the SupportedVersions extension,     causing the server to respond with a TLS 1.2 ServerHello (along with a downgrade canary in the ServerHello     random field). Because uTLS did not check the downgrade canary in the ServerHello random field, clients     would accept the downgraded connection without detecting the attack. This attack could also be used by an     active network attacker to fingerprint uTLS connections. This issue has been fixed in version 1.7.0.
    (CVE-2026-26994)

Note that Nessus relies on the presence of the package as reported by the vendor.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - uTLS is a fork of crypto/tls, created to customize ClientHello for fingerprinting resistance while still
    using it for the handshake. In versions 1.6.7 and below, uTLS did not implement the TLS 1.3 downgrade
    protection mechanism specified in RFC 8446 Section 4.1.3 when using a uTLS ClientHello spec. This allowed
    an active network adversary to downgrade TLS 1.3 connections initiated by a uTLS client to a lower TLS
    version (e.g., TLS 1.2) by modifying the ClientHello message to exclude the SupportedVersions extension,
    causing the server to respond with a TLS 1.2 ServerHello (along with a downgrade canary in the ServerHello
    random field). Because uTLS did not check the downgrade canary in the ServerHello random field, clients
    would accept the downgraded connection without detecting the attack. This attack could also be used by an
    active network attacker to fingerprint uTLS connections. This issue has been fixed in version 1.7.0.
    (CVE-2026-26994)

ID	Name	Product	Family	Severity
299752	Linux Distros Unpatched Vulnerability : CVE-2026-26994	Nessus	Misc.	medium
437859	SCA: security update for github.com/refraction-networking/utls (GHSA-pmc3-p9hx-jq96)	Tenable Cloud Security	SCA Checks	medium
437859	SCA: security update for github.com/refraction-networking/utls (GHSA-pmc3-p9hx-jq96)	Tenable Self-Hosted Container Security	SCA Checks	medium

Detections

Analytics

CVE-2026-26994

medium

Tenable Plugins

medium

medium

medium