GHSA-965h-392x-2mh5: rustls-webpki (CVE-2026-93600)

Name constraints for URI names were incorrectly accepted

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-965h-392x-2mh5 · CVE-2026-93600 · RUSTSEC-2026-0098

Weakness (CWE)

CWE-295

Machine-written summary

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

rustls-webpki versions before 0.103.12 and from 0.104.0-alpha.1 before 0.104.0-alpha.6 accepted URI name constraints in certificates without enforcing them, because the constraints were ignored. An attacker would need a certificate misissued by a certificate authority to exploit this, since the flaw only applies after signature verification succeeds. 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.