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CVE-2023-50868The Closest Encloser Proof aspect of the DNS protocol (in RFC 5155 when RFC 9276 guidance is skipped) allows remote attackers to cause a…
- 7.5HighCVSS base score
- 74.3%Exploitation in 30 daysEPSS · top 0.5% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By mitre
- 2 months later
· 2 months later
Published
- 21 months later
· 21 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CISA-ADPADP (enrichment) | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
| NVDNVD · Analyzed | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 74.3% · top 0.5% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Affected products
n/a
- affected n/a
References
References29
- https://nlnetlabs.nl/news/2024/Feb/13/unbound-1.19.1-released/ (opens in a new tab)x_transferred
- https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-2024-01.html (opens in a new tab)x_transferred
- https://www.isc.org/blogs/2024-bind-security-release/ (opens in a new tab)x_transferred
- https://datatracker.ietf.org/doc/html/rfc5155 (opens in a new tab)x_transferred
- https://kb.isc.org/docs/cve-2023-50868 (opens in a new tab)x_transferred
- https://gitlab.nic.cz/knot/knot-resolver/-/releases/v5.7.1 (opens in a new tab)x_transferred
- https://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2024q1/017430.html (opens in a new tab)x_transferred
- https://access.redhat.com/security/cve/CVE-2023-50868 (opens in a new tab)x_transferred
- https://bugzilla.suse.com/show_bug.cgi?id=1219826 (opens in a new tab)x_transferred
- [oss-security] 20240216 Re: Unbound: disclosure of CVE-2023-50387 and CVE-2023-50868 DNSSEC validation vulnerabilities (opens in a new tab)mailing-listx_transferred
- [oss-security] 20240216 Re: Unbound: disclosure of CVE-2023-50387 and CVE-2023-50868 DNSSEC validation vulnerabilities (opens in a new tab)mailing-listx_transferred
- FEDORA-2024-2e26eccfcb (opens in a new tab)vendor-advisoryx_transferred
- FEDORA-2024-e24211eff0 (opens in a new tab)vendor-advisoryx_transferred
- FEDORA-2024-21310568fa (opens in a new tab)vendor-advisoryx_transferred
- [debian-lts-announce] 20240221 [SECURITY] [DLA 3736-1] unbound security update (opens in a new tab)mailing-listx_transferred
- FEDORA-2024-b0f9656a76 (opens in a new tab)vendor-advisoryx_transferred
- FEDORA-2024-4e36df9dfd (opens in a new tab)vendor-advisoryx_transferred
- FEDORA-2024-499b9be35f (opens in a new tab)vendor-advisoryx_transferred
- FEDORA-2024-c36c448396 (opens in a new tab)vendor-advisoryx_transferred
- FEDORA-2024-c967c7d287 (opens in a new tab)vendor-advisoryx_transferred
- FEDORA-2024-e00eceb11c (opens in a new tab)vendor-advisoryx_transferred
- FEDORA-2024-fae88b73eb (opens in a new tab)vendor-advisoryx_transferred
- https://security.netapp.com/advisory/ntap-20240307-0008/ (opens in a new tab)x_transferred
- [debian-lts-announce] 20240517 [SECURITY] [DLA 3816-1] bind9 security update (opens in a new tab)mailing-listx_transferred
- https://lists.debian.org/debian-lts-announce/2024/11/msg00035.html (opens in a new tab)
- https://lists.debian.org/debian-lts-announce/2024/09/msg00001.html (opens in a new tab)
- https://lists.fedoraproject.org/archives/list/[email protected]/message/ZDZFMEKQTZ4L7RY46FCENWFB5MDT263R/ (opens in a new tab)
- https://lists.fedoraproject.org/archives/list/[email protected]/message/HVRDSJVZKMCXKKPP6PNR62T7RWZ3YSDZ/ (opens in a new tab)
- https://lists.fedoraproject.org/archives/list/[email protected]/message/BUIP7T7Z4T3UHLXFWG6XIVDP4GYPD3AI/ (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2023-55601 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2023-50868)Record last updated .