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Update module github.com/refraction-networking/utls to v1.7.0 [SECURITY]

Renovate Botrequested to merge
renovate/go-github.com-refraction-networking-utls-vulnerability into main

This MR contains the following updates:

Package Type Update Change
github.com/refraction-networking/utls require minor v1.6.7 -> v1.7.0

uTLS ServerHellos are accepted without checking TLS 1.3 downgrade canaries

GHSA-pmc3-p9hx-jq96 / GO-2025-3638

More information

Details

Description

Before version 1.7.0, 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.

Fix Commit or Merge Request

refraction-networking/utls#337, specifically refraction-networking/utls@f8892761e2a4d29054264651d3a86fda83bc83f9

References

Severity

  • CVSS Score: 6.5 / 10 (Medium)
  • Vector String: CVSS:3.1/AV:N/AC:L/MR:N/UI:N/S:U/C:L/I:L/A:N

References

This data is provided by OSV and the GitHub Advisory Database (CC-BY 4.0).

ServerHellos are accepted without checking TLS 1.3 downgrade canaries in github.com/refraction-networking/utls

GHSA-pmc3-p9hx-jq96 / GO-2025-3638

More information

Details

Before version 1.7.0, 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.

Severity

Unknown

References

This data is provided by OSV and the Go Vulnerability Database (CC-BY 4.0).

Release Notes

refraction-networking/utls (github.com/refraction-networking/utls)

v1.7.0

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What's Changed

New Contributors

Full Changelog: https://github.com/refraction-networking/utls/compare/v1.6.7...v1.7.0

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