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
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 3%CVSS: 9.8Exploit: NoneExposed: 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)
EPSS
86.3%
KEV
Not listed

Published

October 30, 2019

Last Modified

November 21, 2024

Advisory Details (9)

Auto-updated Jun 22, 2026
🔬 Proof of concept available. Upstream fix merged — awaiting tagged release. Sources: github_pr.
generic🟡 PoC Available

DNS Encryption Explained

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

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 12× in last 7d / 48× 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.

  1. 2026-07-06 16:24 UTCEPSS rescore
  2. 2026-07-06 16:24 UTCEPSS rescore
  3. 2026-07-06 02:20 UTCEPSS rescore
  4. 2026-07-05 02:27 UTCEPSS rescore
  5. 2026-07-04 06:28 UTCEPSS rescore
  6. 2026-07-04 06:28 UTCEPSS rescore
  7. 2026-07-02 17:56 UTCOSV refresh
  8. 2026-07-02 16:54 UTCEPSS rescore
  9. 2026-07-01 15:03 UTCEPSS rescore
  10. 2026-07-01 15:03 UTCEPSS rescore
  11. 2026-06-30 23:20 UTCEPSS rescore
  12. 2026-06-30 23:19 UTCEPSS rescore
  13. 2026-06-28 04:53 UTCEPSS rescore
  14. 2026-06-28 04:53 UTCEPSS rescore
  15. 2026-06-27 03:06 UTCEPSS rescore
  16. 2026-06-27 03:06 UTCEPSS rescore
  17. 2026-06-25 13:47 UTCEPSS rescore
  18. 2026-06-25 13:47 UTCEPSS rescore
  19. 2026-06-24 14:02 UTCEPSS rescore
  20. 2026-06-24 14:02 UTCEPSS rescore
  21. 2026-06-23 21:30 UTCEPSS rescore
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  23. 2026-06-23 21:30 UTCEPSS rescore
  24. 2026-06-22 14:23 UTCEPSS rescore
  25. 2026-06-21 01:57 UTCEPSS rescore
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  1. 2026-06-21 01:57 UTCEPSS rescore
  2. 2026-06-19 19:23 UTCEPSS rescore
  3. 2026-06-19 19:23 UTCEPSS rescore
  4. 2026-06-18 17:50 UTCEPSS rescore
  5. 2026-06-18 17:50 UTCEPSS rescore
  6. 2026-06-17 17:50 UTCEPSS rescore
  7. 2026-06-17 17:50 UTCEPSS rescore
  8. 2026-06-16 17:50 UTCEPSS rescore
  9. 2026-06-16 17:50 UTCEPSS rescore
  10. 2026-06-15 17:45 UTCEPSS rescore
  11. 2026-06-14 23:15 UTCEPSS rescore
  12. 2026-06-14 23:14 UTCEPSS rescore
  13. 2026-06-14 15:43 UTCOSV refresh
  14. 2026-06-13 22:58 UTCEPSS rescore
  15. 2026-06-12 23:09 UTCEPSS rescore
  16. 2026-06-12 23:09 UTCEPSS rescore
  17. 2026-06-11 13:57 UTCEPSS rescore
  18. 2026-06-10 22:16 UTCEPSS rescore
  19. 2026-06-10 13:19 UTCEPSS rescore
  20. 2026-06-08 14:14 UTCEPSS rescore
  21. 2026-06-08 14:14 UTCEPSS rescore
  22. 2026-06-07 15:22 UTCEPSS rescore
  23. 2026-06-07 15:22 UTCEPSS rescore
  24. 2026-06-06 13:45 UTCEPSS rescore
  25. 2026-06-06 13:45 UTCEPSS rescore
  26. 2026-06-05 22:45 UTCEPSS rescore
  27. 2026-06-05 22:45 UTCEPSS rescore
  28. 2026-06-05 06:08 UTCEPSS rescore
  29. 2026-06-05 06:08 UTCEPSS rescore
  30. 2026-06-04 13:10 UTCEPSS rescore
  31. 2026-06-02 20:11 UTCEPSS rescore
  32. 2026-06-02 20:11 UTCEPSS rescore
  33. 2026-06-01 13:50 UTCEPSS rescore
  34. 2026-06-01 13:50 UTCEPSS rescore
  35. 2026-05-31 22:29 UTCEPSS rescore
  36. 2026-05-31 00:14 UTCEPSS rescore
  37. 2026-05-31 00:14 UTCEPSS rescore
  38. 2026-05-29 13:41 UTCEPSS rescore
  39. 2026-05-28 13:42 UTCEPSS rescore
  40. 2026-05-28 13:42 UTCEPSS rescore
  41. 2026-05-27 13:38 UTCEPSS rescore
  42. 2026-05-27 13:38 UTCEPSS rescore
  43. 2026-05-27 12:24 UTCEG score recompute
  44. 2026-05-27 12:24 UTCVendor advisory
  45. 2026-05-27 12:24 UTCGHSA enrichment
  46. 2026-05-26 13:42 UTCEPSS rescore
  47. 2026-05-26 13:42 UTCEPSS rescore
  48. 2026-05-26 07:17 UTCEPSS rescore
  49. 2026-05-26 07:17 UTCEPSS rescore

Related CVEs(same vendor + same CWE)

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 86.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
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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