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🛡️ CVE-2026-9648 — crypton-x509

🔴 CVSS 9.1 — Critical ✅ No Known Exploit NVD
9.1
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

crypton-x509-validation and crypton-x509 do not enforce X.509 Name Constraints

# crypton-x509-validation and crypton-x509 do not enforce X.509 Name Constraints

The crypton-x509-validation and crypton-x509 libraries did not

enforce the X.509 Name Constraints extension during certificate

validation. The Name Constraints extension is a critical X.509

extension that restricts the namespace (permitted and excluded

subtrees) for which a CA is authorized to issue certificates.

Without this enforcement, a TLS client would accept certificates with

Subject Alternative Names (SANs) that fall outside the issuing CA's

permitted subtrees. An attacker with access to a name-constrained

sub-CA's private key could therefore issue certificates for domains

outside the sub-CA's intended scope, enabling impersonation of

arbitrary domains and man-in-the-middle attacks on TLS connections.

The older x509 and x509-validation packages are also affected but

are no longer maintained and have no fix available.

This issue was fixed in crypton-x509-validation-1.9.1 and

crypton-x509-1.9.1.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability none.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: None.

Affected software

CVE-2026-9648 is recorded against 5 packages.

  • crypton-x509 (from 1.7.6 up to 1.9.1)
  • crypton-x509-validation (from 1.6.12 up to 1.9.1)
  • unknown
  • x509 (from 1.4.0)
  • x509-validation (from 1.4.0)

Timeline and source

Published on 3 June 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.

References

www.kb.cert.org (Advisory)
github.com (Fix)

CVE-2026-9648 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Critical
CVSS Score 9.1
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CWE N/A
Public Exploit ✅ No
Source NVD
Published 2026-06-03
Updated 2026-08-20
Modified 2026-06-03

Affected Packages

Software From version Fixed in
crypton-x509 1.7.6 1.9.1
crypton-x509-validation 1.6.12 1.9.1
unknown — —
x509 1.4.0 —
x509-validation 1.4.0 —

Similar Threats

Exploit Protection

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