CVE-2023-50868

Name: CVE-2023-50868
Creator: NVD / NIST
Published: 2024-02-14T16:15:45.377+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 81.73%

Last modified Jun 17, 2026

CVE-2023-50868 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. The Closest Encloser Proof aspect of the DNS protocol (in RFC 5155 when RFC 9276 guidance is skipped) allows remote attackers to cause a denial of service (CPU consumption for SHA-1 computations) via DNSSEC responses in a random subdomain attack, aka the "NSEC3" issue. The RFC 5155 specification implies that an algorithm must perform thousands of iterations of a hash function in certain situations.. EPSS estimates a 81.73% chance of exploitation in the next 30 days.

Description

The Closest Encloser Proof aspect of the DNS protocol (in RFC 5155 when RFC 9276 guidance is skipped) allows remote attackers to cause a denial of service (CPU consumption for SHA-1 computations) via DNSSEC responses in a random subdomain attack, aka the "NSEC3" issue. The RFC 5155 specification implies that an algorithm must perform thousands of iterations of a hash function in certain situations.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

81.73%

99.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-400

Affected Software

Vendor	Product	Versions	Update
Netapp	Hci Baseboard Management Controller	All versions	—
Netapp	Active Iq Unified Manager	All versions	—
Netapp	Bootstrap Os	All versions	—
Powerdns	Recursor	< 4.8.5	—
Powerdns	Recursor	>= 4.9.0, < 4.9.3	—
Powerdns	Recursor	>= 5.0.0, < 5.0.2	—
Redhat	Enterprise Linux	6.0	—
Redhat	Enterprise Linux	7.0	—
Redhat	Enterprise Linux	8.0	—
Redhat	Enterprise Linux	8.2	—
Redhat	Enterprise Linux	8.4	—
Debian	Debian Linux	10.0	—
Debian	Debian Linux	11.0	—
Fedoraproject	Fedora	38	—
Fedoraproject	Fedora	39	—
Isc	Bind	>= 9.0.0, < 9.16.48	—
Isc	Bind	>= 9.9.3, < 9.16.48	—
Isc	Bind	>= 9.18.0, < 9.18.24	—
Isc	Bind	>= 9.18.11, < 9.18.24	S1
Isc	Bind	>= 9.19.0, < 9.19.21	—

References

http://www.openwall.com/lists/oss-security/2024/02/16/2Issue Tracking, Mailing List
http://www.openwall.com/lists/oss-security/2024/02/16/3Issue Tracking, Mailing List
https://access.redhat.com/security/cve/CVE-2023-50868Vendor Advisory
https://bugzilla.suse.com/show_bug.cgi?id=1219826Issue Tracking
https://datatracker.ietf.org/doc/html/rfc5155Technical Description
https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-2024-01.htmlVendor Advisory
https://gitlab.nic.cz/knot/knot-resolver/-/releases/v5.7.1Release Notes
https://kb.isc.org/docs/cve-2023-50868Third Party Advisory
https://lists.debian.org/debian-lts-announce/2024/02/msg00006.htmlMailing List, Vendor Advisory
https://lists.debian.org/debian-lts-announce/2024/05/msg00011.htmlMailing List, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6FV5O347JTX7P5OZA6NGO4MKTXRXMKOZ/Mailing List, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BUIP7T7Z4T3UHLXFWG6XIVDP4GYPD3AI/Mailing List, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HVRDSJVZKMCXKKPP6PNR62T7RWZ3YSDZ/Mailing List, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IGSLGKUAQTW5JPPZCMF5YPEYALLRUZZ6/Mailing List, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PNNHZSZPG2E7NBMBNYPGHCFI4V4XRWNQ/Mailing List, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RGS7JN6FZXUSTC2XKQHH27574XOULYYJ/Mailing List, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SVYA42BLXUCIDLD35YIJPJSHDIADNYMP/Mailing List, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TEXGOYGW7DBS3N2QSSQONZ4ENIRQEAPG/Mailing List, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UQESRWMJCF4JEYJEAKLRM6CT55GLJAB7/Mailing List, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZDZFMEKQTZ4L7RY46FCENWFB5MDT263R/Mailing List, Vendor Advisory
https://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2024q1/017430.htmlMailing List, Release Notes
https://nlnetlabs.nl/news/2024/Feb/13/unbound-1.19.1-released/Release Notes
https://security.netapp.com/advisory/ntap-20240307-0008/Vendor Advisory
https://www.isc.org/blogs/2024-bind-security-release/Exploit, Mitigation, Press/Media Coverage
http://www.openwall.com/lists/oss-security/2024/02/16/2Issue Tracking, Mailing List
http://www.openwall.com/lists/oss-security/2024/02/16/3Issue Tracking, Mailing List
https://access.redhat.com/security/cve/CVE-2023-50868Vendor Advisory
https://bugzilla.suse.com/show_bug.cgi?id=1219826Issue Tracking
https://datatracker.ietf.org/doc/html/rfc5155Technical Description
https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-2024-01.htmlVendor Advisory
https://gitlab.nic.cz/knot/knot-resolver/-/releases/v5.7.1Release Notes
https://kb.isc.org/docs/cve-2023-50868Third Party Advisory
https://lists.debian.org/debian-lts-announce/2024/02/msg00006.htmlMailing List, Vendor Advisory
https://lists.debian.org/debian-lts-announce/2024/05/msg00011.htmlMailing List, Vendor Advisory
https://lists.debian.org/debian-lts-announce/2024/09/msg00001.htmlMailing List, Vendor Advisory
https://lists.debian.org/debian-lts-announce/2024/11/msg00035.htmlMailing List, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6FV5O347JTX7P5OZA6NGO4MKTXRXMKOZ/Mailing List, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BUIP7T7Z4T3UHLXFWG6XIVDP4GYPD3AI/Mailing List, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HVRDSJVZKMCXKKPP6PNR62T7RWZ3YSDZ/Mailing List, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IGSLGKUAQTW5JPPZCMF5YPEYALLRUZZ6/Mailing List, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PNNHZSZPG2E7NBMBNYPGHCFI4V4XRWNQ/Mailing List, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RGS7JN6FZXUSTC2XKQHH27574XOULYYJ/Mailing List, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SVYA42BLXUCIDLD35YIJPJSHDIADNYMP/Mailing List, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TEXGOYGW7DBS3N2QSSQONZ4ENIRQEAPG/Mailing List, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UQESRWMJCF4JEYJEAKLRM6CT55GLJAB7/Mailing List, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZDZFMEKQTZ4L7RY46FCENWFB5MDT263R/Mailing List, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/BUIP7T7Z4T3UHLXFWG6XIVDP4GYPD3AI/Mailing List, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/HVRDSJVZKMCXKKPP6PNR62T7RWZ3YSDZ/Mailing List, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZDZFMEKQTZ4L7RY46FCENWFB5MDT263R/Mailing List, Vendor Advisory
https://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2024q1/017430.htmlMailing List, Release Notes
https://nlnetlabs.nl/news/2024/Feb/13/unbound-1.19.1-released/Release Notes
https://security.netapp.com/advisory/ntap-20240307-0008/Vendor Advisory
https://www.isc.org/blogs/2024-bind-security-release/Exploit, Mitigation, Press/Media Coverage

Timeline

Published: Feb 14, 2024
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2023-50868?

How severe is CVE-2023-50868?

CVE-2023-50868 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 81.73% probability of exploitation in the next 30 days.

How do I fix CVE-2023-50868?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2023-50868?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST