CVE-2023-50868
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…
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 74.3%, higher than 99% of all known CVEs. Patch or mitigate before the next change window.
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 74.30% probability · 99th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-400
- Affected
- netapp/hci baseboard management controller · netapp/active iq unified manager · netapp/bootstrap os · powerdns/recursor · redhat/enterprise linux · debian/debian linux · fedoraproject/fedora · isc/bind
- Source
- cve@mitre.org
EPSS moved from 73.7% on 29 September 2026 to 74.3% on 26 October 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.
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
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.