Microsoft · rustls webpki 0.101.0 before 0.103.12 Name Constraint Bypass
Affects MicrosoftSource GCVE Database
Not known to be exploited · CVSS 2.1 Low : upgrade to 0.104.0-alpha.6 or 0.103.12 when convenient.
Data as of 2 Nov 2026, 10:58 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 0.104.0-alpha.6, 0.103.12
CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 18 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2 Nov 2026.
What to do
Upgrade webpki and rustls/webpki to 0.104.0-alpha.6 or 0.103.12.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| rustlswebpki | Affected
| Fixed in
|
| rustlswebpki | Affected
| Fixed in
|
crates.iorustls/webpkipkg:cargo/rustls/webpkiOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
A vulnerability identified as CVE-2026-93601 affects rustls webpki versions before 0.103.12, specifically version 3.0 of the Microsoft product. The issue involves a Name Constraint Bypass, which relates to certificate validation weaknesses. No CVSS score or detailed impact information is provided.