--- title: "CVE-2023-50387: Certain DNSSEC aspects of the DNS… | CubePath" 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…" language: en source: https://cubepath.com/security/cve/CVE-2023-50387 --- # CVE-2023-50387: Certain DNSSEC aspects of the DNS… | CubePath ## 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. Official description from the CVE record, published by mitre. Copyright © 1999-2026 The MITRE Corporation. See [/security/cve/legal](https://cubepath.com/security/cve/legal) for the CVE license. [View the record on cve.org](https://www.cve.org/CVERecord?id=CVE-2023-50387) ## Key data ### CVSS 3.1 High 7.5 Score published by CISA-ADP in the CVE record. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | Metric | Value | What it means | | ---------------------- | --------- | ----------------------------------------------------------------------------------- | | Attack vector | Network | The vulnerable component can be reached over a network, possibly from the Internet. | | Attack complexity | Low | No special conditions are needed. The attack can be repeated at will. | | Privileges required | None | No account or privileges are needed. | | User interaction | None | No action from any user is needed. | | Scope | Unchanged | The impact stays within the vulnerable component. | | Confidentiality impact | None | No effect on the secrecy of data. | | Integrity impact | None | No effect on the trustworthiness of data. | | Availability impact | High | Serious or total effect on availability. | CVSS is owned and managed by FIRST.Org, Inc. (FIRST) and is used by permission. Each CVSS score on this site is shown together with its vector string, as published in the CVE record by the source named next to it. Learn more at [first.org/cvss](https://www.first.org/cvss/) . ### EPSS Exploit Prediction Scoring System by FIRST: an estimate of the probability that exploitation activity will be observed in the next 30 days. Score 0.99990 (99.99% probability) Percentile 99.98% Scores of Nov 10, 2026 Model v2026.06.15 ### CISA assessment as of May 8, 2025 Stakeholder-Specific Vulnerability Categorization (SSVC) decision points added by CISA. Automatable yes Technical impact partial ### Weakness (CWE) CWE catalog version 5.0. CWE names: Copyright © 2006-2026, The MITRE Corporation. See [/security/cve/legal](https://cubepath.com/security/cve/legal) for the CWE license. - [CWE-770](https://cwe.mitre.org/data/definitions/770.html) Allocation of Resources Without Limits or Throttling ## References Links listed in the CVE record. They lead to other sites, which CubePath does not control. - [athene-center.de/aktuelles/key-trap](https://www.athene-center.de/aktuelles/key-trap) - [nlnetlabs.nl/news/2024/Feb/13/unbound-1.19.1-released](https://nlnetlabs.nl/news/2024/Feb/13/unbound-1.19.1-released/) - [kb.isc.org/docs/cve-2023-50387](https://kb.isc.org/docs/cve-2023-50387) - [docs.powerdns.com/recursor/security-advisories/powerdns-adv…](https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-2024-01.html) - [theregister.com/2024/02/13/dnssec\_vulnerability\_internet](https://www.theregister.com/2024/02/13/dnssec%5Fvulnerability%5Finternet/) - [news.ycombinator.com/item?id=39367411](https://news.ycombinator.com/item?id=39367411) - [securityweek.com/keytrap-dns-attack-could-disable-large-par…](https://www.securityweek.com/keytrap-dns-attack-could-disable-large-parts-of-internet-researchers/) - [isc.org/blogs/2024-bind-security-release](https://www.isc.org/blogs/2024-bind-security-release/) - [news.ycombinator.com/item?id=39372384](https://news.ycombinator.com/item?id=39372384) - [gitlab.nic.cz/knot/knot-resolver/-/releases/v5.7.1](https://gitlab.nic.cz/knot/knot-resolver/-/releases/v5.7.1) - [lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2024q1/01…](https://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2024q1/017430.html) - [msrc.microsoft.com/update-guide/vulnerability/CVE-2023-50387](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-50387) - [access.redhat.com/security/cve/CVE-2023-50387](https://access.redhat.com/security/cve/CVE-2023-50387) - [bugzilla.suse.com/show\_bug.cgi?id=1219823](https://bugzilla.suse.com/show%5Fbug.cgi?id=1219823) - [athene-center.de/fileadmin/content/PDF/Technical\_Report\_Key…](https://www.athene-center.de/fileadmin/content/PDF/Technical%5FReport%5FKeyTrap.pdf) - [\[oss-security\] 20240216 Re: Unbound: disclosure of CVE-2023-50387 and CVE-2023-50868 DNSSEC validation vulnerabilities](http://www.openwall.com/lists/oss-security/2024/02/16/2) (openwall.com) mailing-list - [\[oss-security\] 20240216 Re: Unbound: disclosure of CVE-2023-50387 and CVE-2023-50868 DNSSEC validation vulnerabilities](http://www.openwall.com/lists/oss-security/2024/02/16/3) (openwall.com) mailing-list - [FEDORA-2024-2e26eccfcb](https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SVYA42BLXUCIDLD35YIJPJSHDIADNYMP/) (lists.fedoraproject.org) vendor-advisory - [FEDORA-2024-e24211eff0](https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BUIP7T7Z4T3UHLXFWG6XIVDP4GYPD3AI/) (lists.fedoraproject.org) vendor-advisory - [FEDORA-2024-21310568fa](https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PNNHZSZPG2E7NBMBNYPGHCFI4V4XRWNQ/) (lists.fedoraproject.org) vendor-advisory - [\[debian-lts-announce\] 20240221 \[SECURITY\] \[DLA 3736-1\] unbound security update](https://lists.debian.org/debian-lts-announce/2024/02/msg00006.html) (lists.debian.org) mailing-list - [FEDORA-2024-b0f9656a76](https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TEXGOYGW7DBS3N2QSSQONZ4ENIRQEAPG/) (lists.fedoraproject.org) vendor-advisory - [FEDORA-2024-4e36df9dfd](https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UQESRWMJCF4JEYJEAKLRM6CT55GLJAB7/) (lists.fedoraproject.org) vendor-advisory - [FEDORA-2024-499b9be35f](https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RGS7JN6FZXUSTC2XKQHH27574XOULYYJ/) (lists.fedoraproject.org) vendor-advisory - [FEDORA-2024-c36c448396](https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HVRDSJVZKMCXKKPP6PNR62T7RWZ3YSDZ/) (lists.fedoraproject.org) vendor-advisory - [FEDORA-2024-c967c7d287](https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6FV5O347JTX7P5OZA6NGO4MKTXRXMKOZ/) (lists.fedoraproject.org) vendor-advisory - [FEDORA-2024-e00eceb11c](https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IGSLGKUAQTW5JPPZCMF5YPEYALLRUZZ6/) (lists.fedoraproject.org) vendor-advisory - [FEDORA-2024-fae88b73eb](https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZDZFMEKQTZ4L7RY46FCENWFB5MDT263R/) (lists.fedoraproject.org) vendor-advisory - [security.netapp.com/advisory/ntap-20240307-0007](https://security.netapp.com/advisory/ntap-20240307-0007/) - [\[debian-lts-announce\] 20240517 \[SECURITY\] \[DLA 3816-1\] bind9 security update](https://lists.debian.org/debian-lts-announce/2024/05/msg00011.html) (lists.debian.org) mailing-list - [lists.debian.org/debian-lts-announce/2024/11/msg00035.html](https://lists.debian.org/debian-lts-announce/2024/11/msg00035.html) - [lists.debian.org/debian-lts-announce/2024/09/msg00001.html](https://lists.debian.org/debian-lts-announce/2024/09/msg00001.html) - [lists.fedoraproject.org/archives/list/package-announce@list…](https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZDZFMEKQTZ4L7RY46FCENWFB5MDT263R/) - [lists.fedoraproject.org/archives/list/package-announce@list…](https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/HVRDSJVZKMCXKKPP6PNR62T7RWZ3YSDZ/) - [lists.fedoraproject.org/archives/list/package-announce@list…](https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/RGS7JN6FZXUSTC2XKQHH27574XOULYYJ/) - [lists.fedoraproject.org/archives/list/package-announce@list…](https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/BUIP7T7Z4T3UHLXFWG6XIVDP4GYPD3AI/) ## Timeline 1. ID reserved Dec 7, 2023 2. Record published Feb 14, 2024 3. Record last updated Nov 4, 2025 ## Look up another CVE ## About CubePath CubePath is a cloud provider with data centers in Europe and the United States. It offers VPS, bare metal servers and DDoS protection. [Cloud VPS](https://cubepath.com/vps) [DDoS protection](https://cubepath.com/ddos-protection) Data from the CVE Program (MITRE), CISA KEV and FIRST EPSS. CVSS is owned by FIRST and used by permission. Not affiliated with or endorsed by MITRE, CISA or FIRST. Data as of Nov 10, 2026, 20:03 UTC. [Sources and licenses](https://cubepath.com/security/cve/legal)