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© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2026-26994

22
FAUCET Score

CVE-2026-26994 affects uTLS versions 1.6.7 and below, where it failed to implement TLS 1.3 downgrade protection. An active network adversary could exploit this by modifying ClientHello messages to force a downgrade to older, less secure TLS versions like 1.2, without detection by the uTLS client. This vulnerability is rated Medium (CVSS 6.5), requiring no user interaction and having low impact on confidentiality and integrity. There is currently no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
< 1.7.0CPE matchmatch criteria
cpe:2.3:a:refraction-networking:utls:*:*:*:*:*:go:*:*

CVSS Data

CVSS version used by this source: 3.1

6.5MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
LOW
Integrity Impact
LOW
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
2.5
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.27%
Probability of exploitation in next 30 days
EPSS Percentile
18.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0027 is in the 9th percentile among its peer group of 23,723 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

github_advisorypatch availablevia nvd_reference
View patch
gopatch availablevia ghsa
Product: github.com/refraction-networking/utlsFixed in: 1.7.0

Vendor Advisories (1)

goGHSA-pmc3-p9hx-jq96medium

uTLS ServerHellos are accepted without checking TLS 1.3 downgrade canaries

Apr 23, 2025

References

github.com / refraction-networking/utls/commit/f8892761e2a4d29054264651d3a86fda83bc83f9
Patch
github.com / refraction-networking/utls/issues/181
Issue Tracking
github.com / refraction-networking/utls/pull/337
Issue TrackingPatch
github.com / refraction-networking/utls/security/advisories/GHSA-pmc3-p9hx-jq96
PatchVendor Advisory