GHSA-xgp8-3hg3-c2mh CVE-2026-93601 RUSTSEC-2026-0099
webpki: Name constraints were accepted for certificates asserting a wildcard name
- Severity
- 2.1 / 10
- Low · CVSS 4.0
- Exploit chance (EPSS)
- 0.20%
- Chance of exploitation in the next 30 days. Higher than 10.30% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-295 Improper Certificate Validation
- Fix
0.103.12- Upgrade rustls-webpki to this version or later
Description
Permitted subtree name constraints for DNS names were accepted for certificates asserting a wildcard name.
This was incorrect because, given a name constraint of accept.example.com, *.example.com could feasibly allow a name of reject.example.com which is outside the constraint.
This is very similar to CVE-2025-61727.
Since name constraints are restrictions on otherwise properly-issued certificates, this bug is reachable only after signature verification and requires misissuance to exploit.
Affected versions
crates.io
| Package | Vulnerable | Fixed in |
|---|---|---|
| rustls-webpki | >= 0.101.0, < 0.103.12 |
0.103.12 |
| rustls-webpki | >= 0.104.0-alpha.1, < 0.104.0-alpha.6 |
0.104.0-alpha.6 |
| rustls-webpki | >= 0.0.0-0, < 0.103.12>= 0.104.0-alpha.1, < 0.104.0-alpha.6 |
0.103.120.104.0-alpha.6 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
rustls-webpki crates.io → 0.103.12
- cargo
cargo update -p rustls-webpki --precise 0.103.12
Severity breakdown
CVSS 4.0 2.1
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- Attack vector
- Network
- Attack complexity
- High
- Attack requirements
- Present
- Privileges required
- High
- User interaction
- None
- Confidentiality (vulnerable system)
- None
- Integrity (vulnerable system)
- Low
- Availability (vulnerable system)
- None
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
- Exploit maturity
- Not defined
- Scope
- X
CVSS 3.1 2.2
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:N
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- High
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
Weakness
CWE-295: Improper Certificate Validation
The product does not validate, or incorrectly validates, a certificate.
How to prevent it
- Architecture and Design, Implementation: Certificates should be carefully managed and checked to assure that data are encrypted with the intended owner's public key.
- Implementation: If certificate pinning is being used, ensure that all relevant properties of the certificate are fully validated before the certificate is pinned, including the hostname.
References
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| RUSTSEC-2026-0382 Distrust compromised intermediate certificates in crypto/x509 | Medium | Also affects rustls-webpki |
| GHSA-82j2-j2ch-gfr8 rustls-webpki: Denial of service via panic on malformed CRL BIT STRING | High | Also affects rustls-webpki |
| GHSA-965h-392x-2mh5 webpki: Name constraints for URI names were incorrectly accepted | Low | Also affects rustls-webpki |
| GHSA-pwjx-qhcg-rvj4 webpki: CRLs not considered authoritative by Distribution Point due to faulty matching logic | Medium | Also affects rustls-webpki |
| GHSA-fh2r-99q2-6mmg rustls-webpki: CPU denial of service in certificate path building | High | Also affects rustls-webpki |
| GHSA-4487-j8r4-4g2f Forge: verifyCertificateChain() removes trusted CA certificates with the same subject from the CA store | Low | Same weakness, CWE-295 |
| GHSA-5x38-2vff-x55p Forge: X.509 basicConstraints bypass in verifyCertificateChain() via deprecated extension OIDs 2.5.29.10 and 2.5.29.13 | High | Same weakness, CWE-295 |
| EEF-CVE-2026-115693 Custom cacerts or cacertfile do not restrict trust to the pinned CA in hackney | Not rated yet | Same weakness, CWE-295 |
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