CVE-2018-21029: fedoraproject fedora Improper Certificate Validation
Vulnerability summary
CVE-2018-21029 is a critical (CVSS 9.8) Improper Certificate Validation vulnerability in fedoraproject fedora. EPSS estimates a 3.14% chance of exploitation in the next 30 days, higher than 87.7% of scored vulnerabilities. 1 public exploit is recorded.
Advisory lineage
Upstream 0 · Downstream 1 · Related 1Timeline
- 30-10-2019PublishedVulnerability first disclosed.
- 05-08-2024Last modifiedVulnerability information updated.
Description
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 metrics
3 scores · 2 sources · 2 versions- OSV · DebianEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
3.14%
Chance of exploitation in the next 30 days
Percentile
88%
Versus all other CVEs
30-day change
0.00 pp
From 3.14% on 18-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundSystemd
Maturity: poc
Weaknesses
CWE · root causeAffected systems
Debian1 product
- systemd< 244-1
Fedoraproject1 product
- fedoraEOL31
Systemd_project1 product
- systemd≥ 239, < 244
3 vendors · 3 products
References
11 links- github.com/systemd/systemd/blob/v243/src/resolve/resolved-dnstls-gnutls.cX Refsource MISCPatchThird Party Advisory
- github.com/systemd/systemd/blob/v243/man/resolved.conf.xmlX Refsource MISCExploitThird Party Advisory
- github.com/systemd/systemd/blob/v239/man/resolved.conf.xmlX Refsource MISCExploitThird Party Advisory
