CVE-2026-93600
CVE-2026-93600
rustls-webpki (rustls/webpki) versions 0.101.0 through 0.103.11 and 0.104.0-alpha releases before 0.104.0-alpha.6 ignore X.509 name constraints that apply to URI names, causing such constraints to be accepted rather than enforced. Because name constraints are restrictions on otherwise properly issued certificates, the flaw is only reachable after successful signature verification and requires a misissued certificate to exploit; the library also provides no API for asserting URI names, and URI name constraints are otherwise unimplemented. Versions 0.103.12 and 0.104.0-alpha.6 reject URI name constraints unconditionally.
Vulnerability class: Improper Certificate Validation
Published · last modified .
CVSS v3 metric
CVSS v3 base score 2.2 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:N.
EPSS exploit prediction
EPSS: 0.002 (10.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 10th percentile — 10.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000
Weakness classification (CWE)
References
- github.com/rustls/webpki/security/advisories/GHSA-965h-392x-2mh5 (vendor-advisory)
- www.vulncheck.com/advisories/rustls-webpki-name-constraints-uri-validation-bypa… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-93600?
- CVE-2026-93600 is a low-severity vulnerability, classified under Improper Certificate Validation. CVSS score: 2.2/10. Published 2026-09-18.
- How severe is CVE-2026-93600?
- Low severity. CVSS v3 base score is 2.2 out of 10.