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: 3.1%CVSS: 9.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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
9.8CRITICALmedium confidence
EG Risk
50
EG Risk 50/100CISA SSVC

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%
CISA SSVC: Track at low or medium mission impact; Track* or Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
3.1%
EPSS %ILE
87th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* or Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact total (CVSS ≥ 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

October 30, 2019

Last Modified

November 21, 2024

Advisory Details (9)

Auto-updated Oct 6, 2026
Patch available. 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) | RFC Editor

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

Vendor Advisories for CVE-2018-21029(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
systemd—
  • every version up to 244-1: fixed in 244-1
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
systemd—
  • every version up to 244-1: fixed in 244-1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
systemd—
  • every version up to 244-1: fixed in 244-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
systemd—
  • every version up to 244-1: fixed in 244-1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 24× 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 162 total refreshes for this CVE.

  1. 2026-10-05 17:39 UTCEPSS rescore
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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 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 3.1% probability of exploitation in the next 30 days (87th percentile of EPSS-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?
A fix for CVE-2018-21029 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2018-21029 are linked in the Vendor Advisories panel on this page.

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