CVE-2026-26995: Github.com/refraction networking/utls UTLS Has A Fingerprint Vulnerability Vulnerability

LOW
Advisory Identifier: GHSA-rrxv-pmq9-x67r
Share
CWE-200
Published
Advisory Summary

CVE-2026-26995 is a LOW utls has a fingerprint vulnerability vulnerability (CWE-200: Exposure of Sensitive Information to an Unauthorized Actor) affecting Github.com/refraction networking/utls libraries in the Go ecosystem. The issue involves utls has a fingerprint vulnerability from missing padding extension for chrome 120. Remediation is available by upgrading affected packages to version 1.8.2.

CVE-2026-26995 at a Glance

CVE Identifier CVE-2026-26995
GHSA Identifier GHSA-rrxv-pmq9-x67r
Severity LOW
CVSS v3.1 Base Score N/A
CWE Classification CWE-200: Exposure of Sensitive Information to an Unauthorized Actor
Affected Product Github.com/refraction networking/utls
Package Ecosystem Go
Published Date
Last Updated

How to Fix CVE-2026-26995

To remediate this vulnerability, upgrade all affected Github.com/refraction networking/utls dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

github.com/refraction-networking/utls fixed: 1.8.2 
Upgrade github.com/refraction-networking/utls to 1.8.2
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for github.com/refraction-networking/utls

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-26995, inspect your project dependencies for Github.com/refraction networking/utls:

inspect dependencies for github.com/refraction-networking/utls

Analyze the terminal output to locate any version of Github.com/refraction networking/utls in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.8.2), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-200: Exposure of Sensitive Information to an Unauthorized Actor, where the product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. In Github.com/refraction networking/utls, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

The padding extension was incorrectly removed in utls for the non-pq variant of Chrome 120 fingerprint. Chrome removed this extension only when sending pq keyshares. Only this fingerprint is affected since newer fingerprints have pq keyshares by default and older fingerprints have this extension. Affected symbols: `HelloChrome_120` Fix commit: 8fe0b08e9a0e7e2d08b268f451f2c79962e6acd0 Thanks to telegram @acgdaily for reporting this issue.

CVE-2026-26995 Affected Github.com/refraction networking/utls Versions

1 component(s)
Fixed Versions:
1.8.2
Product / Package Ecosystem Affected Versions Fixed Version
github.com/refraction-networking/utls
golang/github.com/refraction-networking/utls
Go
≥ 1.6.0
< 1.8.2
1.8.2

References

GitHub Advisory / Wiki ADVISORY
https://github.com/refraction-networking/utls/security/advisories/GHSA-rrxv-pmq9-x67r
Security Fix Commit FIX COMMIT
https://github.com/refraction-networking/utls/commit/8fe0b08e9a0e7e2d08b268f451f2c79962e6acd0
Github.com/refraction networking/utls Source Repository REPOSITORY
https://github.com/refraction-networking/utls
pkg.go.dev/vuln/go-2026-4512 WEB
https://pkg.go.dev/vuln/GO-2026-4512

Frequently Asked Questions

What is CVE-2026-26995?
CVE-2026-26995 is a security vulnerability in Github.com/refraction networking/utls involving uTLS has a fingerprint vulnerability from missing padding extension for Chrome 120 under CWE-200: Exposure of Sensitive Information to an Unauthorized Actor.
Which Github.com/refraction networking/utls versions are affected?
Affected versions include releases prior to 1.8.2 across affected packages: github.com/refraction-networking/utls.
What version fixes CVE-2026-26995?
Upgrading to 1.8.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is github.com/refraction-networking/utls affected?
Yes, github.com/refraction-networking/utls is affected in releases prior to 1.8.2. Upgrade your dependency to 1.8.2 or later.
What CWE is associated with CVE-2026-26995?
CVE-2026-26995 is classified under CWE-200: Exposure of Sensitive Information to an Unauthorized Actor (The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.).
How can I check Go dependencies for CVE-2026-26995?
Run the dependency tree command: 'inspect dependencies for github.com/refraction-networking/utls'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-rrxv-pmq9-x67r",
  "modified" : "2026-02-27T20:37:52Z",
  "published" : "2026-02-18T22:33:47Z",
  "aliases" : [ "CVE-2026-26995" ],
  "summary" : "uTLS has a fingerprint vulnerability from missing padding extension for Chrome 120",
  "details" : "The padding extension was incorrectly removed in utls for the non-pq variant of Chrome 120 fingerprint. Chrome removed this extension only when sending pq keyshares. Only this fingerprint is affected since newer fingerprints have pq keyshares by default and older fingerprints have this extension.\n\nAffected symbols: `HelloChrome_120`\n\nFix commit: 8fe0b08e9a0e7e2d08b268f451f2c79962e6acd0\n\nThanks to telegram @acgdaily for reporting this issue.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/refraction-networking/utls"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.6.0"
      }, {
        "fixed" : "1.8.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/refraction-networking/utls/security/advisories/GHSA-rrxv-pmq9-x67r"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/refraction-networking/utls/commit/8fe0b08e9a0e7e2d08b268f451f2c79962e6acd0"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/refraction-networking/utls"
  }, {
    "type" : "WEB",
    "url" : "https://pkg.go.dev/vuln/GO-2026-4512"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-200" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-02-18T22:33:47Z",
    "nvd_published_at" : "2026-02-20T03:16:01Z"
  }
}