GHSA-7m29-f4hw-g2vx

Source

https://github.com/advisories/GHSA-7m29-f4hw-g2vx

Import Source

https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/02/GHSA-7m29-f4hw-g2vx/GHSA-7m29-f4hw-g2vx.json

JSON Data

https://api.test.osv.dev/v1/vulns/GHSA-7m29-f4hw-g2vx

Aliases

Downstream

CGA (2)

Published

2026-02-18T22:33:18Z

Modified

2026-07-17T21:12:07Z

Severity

2.3 (Low) CVSS_V4 - 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 CVSS Calculator

Summary

uTLS has a fingerprint vulnerability from GREASE ECH mismatch for Chrome parrots

Details

There is a fingerprint mismatch with Chrome when using GREASE ECH, having to do with ciphersuite selection. When Chrome selects the preferred ciphersuite in the outer ClientHello and the ciphersuite for ECH, it does so consistently based on hardware support. That means, for example, if it prefers AES for the outer ciphersuite, it would also use AES for ECH. The Chrome parrot in utls hardcodes AES preference for outer ciphersuites but selects the ECH ciphersuite randomly between AES and ChaCha20. So there is a 50% chance of selecting ChaCha20 for ECH while using AES for the outer ciphersuite, which is impossible in Chrome.

This is only a problem in GREASE ECH, since in real ECH Chrome selects the first valid ciphersuite when AES is preferred, which is the same in utls. So no change is done there.

Affected symbols: HelloChrome_120, HelloChrome_120_PQ, HelloChrome_131, HelloChrome_133

Fix commit: 24bd1e05a788c1add7f3037f4532ea552b2cee07

Thanks to telegram @acgdaily for reporting this issue.

Database specific

{
    "cwe_ids":  [
        "CWE-1240"
    ],
    "github_reviewed":  true,
    "github_reviewed_at":  "2026-02-18T22:33:18Z",
    "nvd_published_at":  "2026-02-20T03:16:01Z",
    "severity":  "LOW"
}

References

Affected packages

Go / github.com/refraction-networking/utls

Package

Name: github.com/refraction-networking/utls; View open source insights on deps.dev
Purl: pkg:golang/github.com/refraction-networking/utls

Affected ranges

Type: SEMVER
Events: Introduced

1.6.0

Fixed

1.8.1

Database specific

source

"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/02/GHSA-7m29-f4hw-g2vx/GHSA-7m29-f4hw-g2vx.json"