GHSA-xgp8-3hg3-c2mh: rustls-webpki (CVE-2026-93601)

Name constraints were accepted for certificates asserting a wildcard name

CVSS 2.1 LowEPSS 0.0020 · 10th percentile

Published by the GitHub Advisory Database at 14 Apr 2026, 12:00 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

Package	Ecosystem	Affected	Fixed in
rustls-webpki	crates.io	>=0.0.0-0, <0.103.12 \|\| >=0.104.0-alpha.1, <0.104.0-alpha.6	0.103.12, 0.104.0-alpha.6

Identifiers

GHSA-xgp8-3hg3-c2mh · CVE-2026-93601 · RUSTSEC-2026-0099

Weakness (CWE)

CWE-295

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Versions of rustls-webpki before 0.103.12 and from 0.104.0-alpha.1 before 0.104.0-alpha.6 accept permitted DNS name constraints for certificates asserting a wildcard name, so a wildcard name can fall outside the constraint it should respect. Exploiting this requires a certificate that has already been misissued, since the check only applies after signature verification. Upgrade to rustls-webpki 0.103.12 or 0.104.0-alpha.6.

Written 8 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
2.1	Low	4.0	CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N	CNA (VulnCheck)

CISA KEV Not listed.
EPSS 0.0020, the 10th percentile, on 12 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 15:17 UTC First seen by agentprime
31 Oct 2026, 15:17 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.