Security Digest · Critical advisory (no CVE assigned)
GHSA-6q48-6c7w-9gw2: certifi bundles emSign root CAs with compromised intermediate CA keys
Certifi versions before 2026.10.18 include the emSign ECC Root CA - G3 root certificate in their bundled CA store.
CVSS 9.1 Critical GitHub-reviewed · critical
Should you act?
- Only if you depend on one of the packages below, directly or transitively, in a vulnerable version. Check your lockfile with
pip-audit (or: pip show <package>). - No CVE has been assigned, so it will not appear in CVE-based scanners that ignore GitHub advisories.
npm audit,pip-auditand Dependabot do read GitHub advisories.
Affected packages
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| PyPI | certifi | >= 2019.03.09, < 2026.10.19 | 2026.10.19 |
Details
Certifi versions before 2026.10.18 include the emSign ECC Root CA - G3 root certificate in their bundled CA store. Eight eMudhra intermediate CA certificates that chain to this root have compromised private keys and the CA has revoked them.
An attacker with one of the compromised keys can issue valid-looking certificates for any hostname. If the attacker is also on-path, they can intercept or modify TLS traffic from clients that trust the certifi bundle. Examples include requests, urllib3 and pip, and the Python.org macOS installer.
Certifi 2026.10.18 removed all emSign roots from the bundle. Certifi 2026.10.19 restored the emSign roots that are not affected. Upgrade to 2026.10.19 or later, and rebuild container images that vendor certifi.
CVSS: 9.1 (v4.0) CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Sources and references
- GitHub Advisory GHSA-6q48-6c7w-9gw2 github.com
- github.com github.com
- discuss.python.org discuss.python.org
- emudhra.we-have-a-problem.com emudhra.we-have-a-problem.com