Description
The crypton-x509-validation Haskell library fails to enforce X.509 NameConstraints, allowing TLS clients to accept certificates whose Subject Alternative Names fall outside the issuing CA’s permitted subtrees. This oversight enables an attacker who compromises a name-constrained sub-CA to impersonate domains beyond its intended scope.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Haskell Programming Language | crypton-certificate | < 1.9.1 | 1.9.1 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | haskell-crypton-x509 +1 | No fix yet | — |
| Debian 13 | haskell-crypton-x509 +1 | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | haskell-crypton-x509-validation | No fix yet | — |
| Ubuntu 26.04 LTS | haskell-crypton-x509-validation | No fix yet | — |
| Ubuntu 25.10 | haskell-crypton-x509-validation | No fix yet | — |
| Ubuntu 24.04 LTS | haskell-crypton-x509-validation | No fix yet | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | ghc-aws | 0.25.2-1.1 | openSUSE-SU-2026:11077-1 |
| openSUSE Tumbleweed | ghc-crypton-asn1-parse +1 | 0.10.0-1.1 | openSUSE-SU-2026:11079-1, openSUSE-SU-2026:11078-1 |
| openSUSE Tumbleweed | ghc-crypton-asn1-types | 0.4.1-1.1 | openSUSE-SU-2026:11080-1 |
| openSUSE Tumbleweed | ghc-crypton-pem | 0.3.0-1.1 | openSUSE-SU-2026:11081-1 |
| openSUSE Tumbleweed | ghc-crypton-x509 +1 | 1.9.1-1.1 | openSUSE-SU-2026:11085-1, openSUSE-SU-2026:11082-1 |
| openSUSE Tumbleweed | ghc-crypton-x509-store +1 | 1.9.0-1.1 | openSUSE-SU-2026:11084-1, openSUSE-SU-2026:11083-1 |
| openSUSE Tumbleweed | git-annex | 10.20260601-2.1 | openSUSE-SU-2026:11087-1 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Hackage | crypton-x509 | >= 1.7.6, < 1.9.1 | 1.9.1 | HSEC-2026-0008 |
| Hackage | crypton-x509-validation | >= 1.6.12, < 1.9.1 | 1.9.1 | HSEC-2026-0008 |
| Hackage | x509 | >= 1.4.0 | — | HSEC-2026-0008 |
| Hackage | x509-validation | >= 1.4.0 | — | HSEC-2026-0008 |
Advisories 10
- openSUSE-SU-2026:11079-1 ghc-crypton-asn1-parse-0.10.0-1.1 on GA media SUSE / openSUSE Security Updates · Jun 24, 2026
- openSUSE-SU-2026:11080-1 ghc-crypton-asn1-types-0.4.1-1.1 on GA media SUSE / openSUSE Security Updates · Jun 24, 2026
- openSUSE-SU-2026:11084-1 ghc-crypton-x509-system-1.9.0-1.1 on GA media SUSE / openSUSE Security Updates · Jun 24, 2026
- openSUSE-SU-2026:11085-1 ghc-crypton-x509-validation-1.9.1-1.1 on GA media SUSE / openSUSE Security Updates · Jun 24, 2026
- openSUSE-SU-2026:11087-1 git-annex-10.20260601-2.1 on GA media SUSE / openSUSE Security Updates · Jun 24, 2026
- openSUSE-SU-2026:11078-1 ghc-crypton-asn1-encoding-0.10.0-1.1 on GA media SUSE / openSUSE Security Updates · Jun 24, 2026
- openSUSE-SU-2026:11081-1 ghc-crypton-pem-0.3.0-1.1 on GA media SUSE / openSUSE Security Updates · Jun 24, 2026
- openSUSE-SU-2026:11082-1 ghc-crypton-x509-1.9.1-1.1 on GA media SUSE / openSUSE Security Updates · Jun 24, 2026
- openSUSE-SU-2026:11083-1 ghc-crypton-x509-store-1.9.0-1.1 on GA media SUSE / openSUSE Security Updates · Jun 24, 2026
- openSUSE-SU-2026:11077-1 ghc-aws-0.25.2-1.1 on GA media SUSE / openSUSE Security Updates · Jun 24, 2026
References
- https://github.com/kazu-yamamoto/crypton-certificate/pull/30
- https://github.com/kazu-yamamoto/crypton-certificate/pull/30/changes/f4b77edf6ead77f4a886da40e41eab20f0180e39
- https://hackage.haskell.org/package/crypton-x509-validation-1.9.1/revisions/
- https://github.com/haskell/security-advisories/pull/332