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Public proof of conceptFix available

CVE-2023-50387

A public proof of concept exists; no exploitation attested.

  • Published2024-02-14
  • WeaknessCWE-770

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Certain DNSSEC aspects of the DNS protocol (in RFC 4033, 4034, 4035, 6840, and related RFCs) allow remote attackers to cause a denial of service (CPU consumption) via one or more DNSSEC responses, aka the "KeyTrap" issue. One of the concerns is that, when there is a zone with many DNSKEY and RRSIG records, the protocol specification implies that an algorithm must evaluate all combinations of DNSKEY and RRSIG records.

Timeline

dates in UTC
  1. 2024-02-1416:15CVE publishedNVD
  2. 2026-10-2319:23First public proof of conceptPoC-in-GitHub
  3. 2026-10-2319:23EPSS crossed 10 %FIRST EPSS

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2023-50387?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2023-50387?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Redhat enterprise linux
BranchAffectedFixed in
6.0= 6.0no fix published
7.0= 7.0no fix published
8.0= 8.0no fix published
9.0= 9.0no fix published
Isc bind
BranchAffectedFixed in
9.x≥ 9.0.0, ≤ 9.16.46no fix published
9.18≥ 9.18.0, ≤ 9.18.22no fix published
9.19≥ 9.19.0, ≤ 9.19.20no fix published
Powerdns recursor
BranchAffectedFixed in
5.0≥ 5.0.0, < 5.0.25.0.2
4.9≥ 4.9.0, < 4.9.34.9.3
4.8≥ 4.8.0, < 4.8.64.8.6

10 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Advisories and patches

Detection

read 2026-10-23 19:23 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
3 repositories, unverifiedknqyf263/CVE-2023-50387Meirelez/SSR-DNSSECPablodiz/CVE-2023-50387
PoC-in-GitHub

Sources

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2024-02-14
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2023-50387?

Certain DNSSEC aspects of the DNS protocol (in RFC 4033, 4034, 4035, 6840, and related RFCs) allow remote attackers to cause a denial of service (CPU consumption) via one or more DNSSEC responses, aka the "KeyTrap" issue. One of the concerns is that, when there is a zone with many DNSKEY and RRSIG records, the protocol specification implies that an algorithm must evaluate all combinations of DNSKEY and RRSIG records.

Is CVE-2023-50387 actively exploited?

Active exploitation of CVE-2023-50387 has not been confirmed. Its EPSS score was 99.9% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2023-50387?

CVE-2023-50387 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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