Vulnerability Details CVE-2018-21029
systemd 239 through 245 accepts any certificate signed by a trusted certificate authority for DNS Over TLS. Server Name Indication (SNI) is not sent, and there is no hostname validation with the GnuTLS backend. NOTE: This has been disputed by the developer as not a vulnerability since hostname validation does not have anything to do with this issue (i.e. there is no hostname to be sent)
Exploit prediction scoring system (EPSS) score
EPSS Score 0.016
EPSS Ranking 80.5%
CVSS Severity
CVSS v3 Score 9.8
CVSS v2 Score 7.5
References
- https://blog.cloudflare.com/dns-encryption-explained/
- https://github.com/systemd/systemd/blob/v239/man/resolved.conf.xml#L199-L207
- https://github.com/systemd/systemd/blob/v243/man/resolved.conf.xml#L196-L207
- https://github.com/systemd/systemd/blob/v243/src/resolve/resolved-dnstls-gnutls.c#L62-L63
- https://github.com/systemd/systemd/issues/9397
- https://github.com/systemd/systemd/pull/13870
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4NLJVOJMB6ANDILRLDZK26YGLYBEPHKY/
- https://security.netapp.com/advisory/ntap-20191122-0002/
- https://tools.ietf.org/html/rfc7858#section-4.1
- https://blog.cloudflare.com/dns-encryption-explained/
- https://github.com/systemd/systemd/blob/v239/man/resolved.conf.xml#L199-L207
- https://github.com/systemd/systemd/blob/v243/man/resolved.conf.xml#L196-L207
- https://github.com/systemd/systemd/blob/v243/src/resolve/resolved-dnstls-gnutls.c#L62-L63
- https://github.com/systemd/systemd/issues/9397
- https://github.com/systemd/systemd/pull/13870
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4NLJVOJMB6ANDILRLDZK26YGLYBEPHKY/
- https://security.netapp.com/advisory/ntap-20191122-0002/
- https://tools.ietf.org/html/rfc7858#section-4.1
Products affected by CVE-2018-21029
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cpe:2.3:a:systemd_project:systemd:239
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cpe:2.3:a:systemd_project:systemd:240
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cpe:2.3:a:systemd_project:systemd:241
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cpe:2.3:a:systemd_project:systemd:242
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cpe:2.3:a:systemd_project:systemd:243
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cpe:2.3:o:fedoraproject:fedora:31