CVE-2018-21029

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-05-24. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 3%CVSS: 9.8Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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)

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
50(Track)
EG Risk 50/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation3% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
3%
EPSS %ILE
87%
KEV
Not listed

Published

October 30, 2019

Last Modified

November 21, 2024

Advisory Details (9)

Auto-updated Aug 19, 2026
Upstream fix merged — awaiting tagged release. Sources: github_pr.
generic

DNS Encryption Explained | Cloudflare Blog

https://blog.cloudflare.com/dns-encryption-explained/
generic

RFC 7858 - Specification for DNS over Transport Layer Security (TLS)

https://tools.ietf.org/html/rfc7858#section-4.1
generic

NetApp Product Security

https://security.netapp.com/advisory/ntap-20191122-0002/
generic

[SECURITY] Fedora 31 Update: systemd-243.4-1.fc31 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4NLJVOJMB6ANDILRLDZK26YGLYBEPHKY/
github_pr

resolved: validate IP address in certificate for DNS-over-TLS (GnuTLS)

Fix merged in systemd/systemd PR #13870 on 2019-10-30 — awaiting tagged release

https://github.com/systemd/systemd/pull/13870
generic

RFE: Certificate checking for Resolveds DNS over TLS feature · Issue #9397 · systemd/systemd · GitHub

https://github.com/systemd/systemd/issues/9397
generic

systemd/src/resolve/resolved-dnstls-gnutls.c at v243 · systemd/systemd · GitHub

https://github.com/systemd/systemd/blob/v243/src/resolve/resolved-dnstls-gnutls.c#L62-L63
generic

systemd/man/resolved.conf.xml at v243 · systemd/systemd · GitHub

https://github.com/systemd/systemd/blob/v243/man/resolved.conf.xml#L196-L207
generic

systemd/man/resolved.conf.xml at v239 · systemd/systemd · GitHub

https://github.com/systemd/systemd/blob/v239/man/resolved.conf.xml#L199-L207

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
systemd—244-1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
systemd—244-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
systemd—244-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
systemd—244-1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 8× in last 7d / 29× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 127 total refreshes for this CVE.

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Frequently asked(5)

What is CVE-2018-21029?
CVE-2018-21029 is a critical vulnerability published on October 30, 2019. 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…
When was CVE-2018-21029 disclosed?
CVE-2018-21029 was first published in the National Vulnerability Database on October 30, 2019, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2018-21029 actively exploited?
CVE-2018-21029 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 3% probability of exploitation in the next 30 days, which ranks it in the top 13.1% of all scored CVEs.
What is the CVSS score of CVE-2018-21029?
CVE-2018-21029 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2018-21029?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2018-21029, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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