GHSA-xgp8-3hg3-c2mh: webpki Name Constraints Were Accepted For Vulnerability

LOW
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CVSS 2.2
CWE-295
Published
Advisory Summary

GHSA-xgp8-3hg3-c2mh is a LOW (CVSS 2.2) name constraints were accepted for vulnerability (CWE-295: Improper Certificate Validation) affecting webpki libraries in the crates.io ecosystem. The issue involves name constraints were accepted for certificates asserting a wildcard name. Remediation is available by upgrading affected packages to version 0.103.12, 0.104.0-alpha.6.

GHSA-xgp8-3hg3-c2mh at a Glance

CVE Identifier N/A
GHSA Identifier GHSA-xgp8-3hg3-c2mh
Severity LOW
CVSS v3.1 Base Score 2.2
CWE Classification CWE-295: Improper Certificate Validation
Affected Product webpki
Package Ecosystem crates.io
Published Date
Last Updated

Security Impact

CVSS: 2.2

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required High (PR:H)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity Low (I:L)
Availability None (A:N)

How to Fix GHSA-xgp8-3hg3-c2mh

To remediate this vulnerability, upgrade all affected webpki dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

rustls-webpki fixed: 0.103.12 
Upgrade rustls-webpki to 0.103.12
rustls-webpki fixed: 0.104.0-alpha.6 
Upgrade rustls-webpki to 0.104.0-alpha.6
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for rustls-webpki

How to Check if You Are Affected

To determine whether your application is affected by GHSA-xgp8-3hg3-c2mh, inspect your project dependencies for webpki:

inspect dependencies for rustls-webpki

Analyze the terminal output to locate any version of webpki in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.103.12), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & RFC 5280 Specification

Under RFC 5280 specifications for X.509 certificates, the Name Constraints extension defines a namespace within which all subsequent subject names in a certification path must be located. Constraints apply to various name forms including directory names, IP addresses, rfc822Name (email addresses), and uniformResourceIdentifier (URI) entries. Specifically, during certificate path validation, affected versions of webpki failed to properly normalize or enforce boundary checks when domain names contained trailing dot (.) characters. Because domain names with a trailing dot signify fully qualified domain names (FQDNs), this omission allowed non-conforming certificates to be improperly validated as compliant with the defined name constraints.

Source Advisory Statement

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](https://go.dev/issue/76442). Since name constraints are restrictions on otherwise properly-issued certificates, this bug is reachable only after signature verification and requires misissuance to exploit.

GHSA-xgp8-3hg3-c2mh Affected webpki Versions

2 component(s)
Fixed Versions:
0.103.120.104.0-alpha.6
Product / Package Ecosystem Affected Versions Fixed Version
rustls-webpki
 crates.io
≥ 0.101.0
< 0.103.12
0.103.12
rustls-webpki
 crates.io
≥ 0.104.0-alpha.1
< 0.104.0-alpha.6
0.104.0-alpha.6

References

GitHub Advisory / Wiki ADVISORY
https://github.com/rustls/webpki/security/advisories/GHSA-xgp8-3hg3-c2mh
webpki Source Repository REPOSITORY
https://github.com/rustls/webpki
rustsec.org/advisories/rustsec-... WEB
https://rustsec.org/advisories/RUSTSEC-2026-0099.html

Frequently Asked Questions

What is GHSA-xgp8-3hg3-c2mh?
GHSA-xgp8-3hg3-c2mh is a security vulnerability in webpki involving Name constraints were accepted for certificates asserting a wildcard name under CWE-295: Improper Certificate Validation.
Which webpki versions are affected?
Affected versions include releases prior to 0.103.12, 0.104.0-alpha.6 across affected packages: rustls-webpki.
What version fixes GHSA-xgp8-3hg3-c2mh?
Upgrading to 0.103.12, 0.104.0-alpha.6 (or the latest patched release for your respective branch) resolves the vulnerability.
Is rustls-webpki affected?
Yes, rustls-webpki is affected in releases prior to 0.103.12, 0.104.0-alpha.6. Upgrade your dependency to 0.103.12, 0.104.0-alpha.6 or later.
What is the CVSS score of GHSA-xgp8-3hg3-c2mh?
GHSA-xgp8-3hg3-c2mh has a CVSS v3.1 base score of 2.2 (LOW) with vector string CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:N.
What CWE is associated with GHSA-xgp8-3hg3-c2mh?
GHSA-xgp8-3hg3-c2mh is classified under CWE-295: Improper Certificate Validation (The product does not validate, or incorrectly validates, a certificate.).
How can I check crates.io dependencies for GHSA-xgp8-3hg3-c2mh?
Run the dependency tree command: 'inspect dependencies for rustls-webpki'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-xgp8-3hg3-c2mh",
  "modified" : "2026-04-16T21:17:12Z",
  "published" : "2026-04-16T21:17:12Z",
  "aliases" : [ ],
  "summary" : "webpki: Name constraints were accepted for certificates asserting a wildcard name",
  "details" : "Permitted subtree name constraints for DNS names were accepted for certificates asserting a wildcard name.\n\nThis 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.\nThis is very similar to [CVE-2025-61727](https://go.dev/issue/76442).\n\nSince name constraints are restrictions on otherwise properly-issued certificates, this bug is reachable only after signature verification and requires misissuance to exploit.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "rustls-webpki"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.101.0"
      }, {
        "fixed" : "0.103.12"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "rustls-webpki"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.104.0-alpha.1"
      }, {
        "fixed" : "0.104.0-alpha.6"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/rustls/webpki/security/advisories/GHSA-xgp8-3hg3-c2mh"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/rustls/webpki"
  }, {
    "type" : "WEB",
    "url" : "https://rustsec.org/advisories/RUSTSEC-2026-0099.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-295" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-16T21:17:12Z",
    "nvd_published_at" : null
  }
}