CVE-2023-50868

Exp

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.

Published: 2024-02-14 Last update: 2025-12-23 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-50868 is rated High Exploit Risk (77.6/100): CVSS High severity, with high exploitation likelihood (EPSS 12.11%, 94th percentile). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2023-50868

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2023-50868

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-09 12.42% 12.11% -0.31%
2 2026-05-27 11.93% 12.42% +0.49%
3 2026-05-22 — 11.93% —

Full EPSS history (51 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-50868

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2023-50868

OS Trackers for CVE-2023-50868

vendor priority summary link
alpine — CVE-2023-50868: 5 source package rows (bind, dnsmasq, knot-resolver, pdns-recursor, unbound); 171 state rows across 12 repos (3.17-main, 3.18-main, 3.19-community, 3.19-main, 3.20-community, 3.20-main, 3.21-community, 3.21-main, 3.22-community, 3.22-main, edge-community, edge-main); fixed 171, open 0. https://security.alpinelinux.org/vuln/CVE-2023-50868
debian end-of-life CVE-2023-50868 end-of-life priority: Debian including 7 source packages (bind9, dnsjava, …), 35 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 31, open 4. https://security-tracker.debian.org/tracker/CVE-2023-50868
gentoo normal CVE-2023-50868: 1 GLSA(s) (202412-10), 1 atom(s) (net-dns/dnsmasq); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2023-50868
redhat high — https://access.redhat.com/security/cve/CVE-2023-50868
suse high — https://www.suse.com/security/cve/CVE-2023-50868/
ubuntu medium CVE-2023-50868 medium priority: Ubuntu including 7 source packages (bind9, bind9-libs, …), 77 status rows across 11 suites (bionic, focal, jammy, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): released 31, needs-triage 17, not-affected 13, DNE 9, ignored 7. https://ubuntu.com/security/CVE-2023-50868

Affected software / configurations for CVE-2023-50868

Vendor Product Version Raw CPE
isc bind >= 9.0.0, < 9.16.48 cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*
isc bind >= 9.9.3, < 9.16.48 cpe:2.3:a:isc:bind:*:*:*:*:supported_preview:*:*:*
isc bind >= 9.18.0, < 9.18.24 cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*
isc bind >= 9.18.11, < 9.18.24 cpe:2.3:a:isc:bind:*:s1:*:*:supported_preview:*:*:*
isc bind >= 9.19.0, < 9.19.21 cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*
fedoraproject fedora 38 cpe:2.3:o:fedoraproject:fedora:38:*:*:*:*:*:*:*
fedoraproject fedora 39 cpe:2.3:o:fedoraproject:fedora:39:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
debian debian_linux 11.0 cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*
redhat enterprise_linux 6.0 cpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:*
redhat enterprise_linux 7.0 cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
redhat enterprise_linux 8.0 cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
redhat enterprise_linux 8.2 cpe:2.3:o:redhat:enterprise_linux:8.2:*:*:*:*:*:*:*
redhat enterprise_linux 8.4 cpe:2.3:o:redhat:enterprise_linux:8.4:*:*:*:*:*:*:*
powerdns recursor < 4.8.5 cpe:2.3:a:powerdns:recursor:*:*:*:*:*:*:*:*
powerdns recursor >= 4.9.0, < 4.9.3 cpe:2.3:a:powerdns:recursor:*:*:*:*:*:*:*:*
powerdns recursor >= 5.0.0, < 5.0.2 cpe:2.3:a:powerdns:recursor:*:*:*:*:*:*:*:*
netapp bootstrap_os — cpe:2.3:o:netapp:bootstrap_os:-:*:*:*:*:*:*:*
netapp active_iq_unified_manager — cpe:2.3:a:netapp:active_iq_unified_manager:-:*:*:*:*:vmware_vsphere:*:*
netapp hci_baseboard_management_controller — cpe:2.3:a:netapp:hci_baseboard_management_controller:-:*:*:*:*:*:*:*

References for CVE-2023-50868

URL Tags
http://www.openwall.com/lists/oss-security/2024/02/16/2 Issue Tracking Mailing List
http://www.openwall.com/lists/oss-security/2024/02/16/3 Issue Tracking Mailing List
https://access.redhat.com/security/cve/CVE-2023-50868 Vendor Advisory
https://bugzilla.suse.com/show_bug.cgi?id=1219826 Issue Tracking
https://datatracker.ietf.org/doc/html/rfc5155 Technical Description
https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-2024-01.html Vendor Advisory
https://gitlab.nic.cz/knot/knot-resolver/-/releases/v5.7.1 Release Notes
https://kb.isc.org/docs/cve-2023-50868 Third Party Advisory
https://lists.debian.org/debian-lts-announce/2024/02/msg00006.html Vendor Advisory Mailing List
https://lists.debian.org/debian-lts-announce/2024/05/msg00011.html Vendor Advisory Mailing List
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6FV5O347JTX7P5OZA6NGO4MKTXRXMKOZ/ Vendor Advisory Mailing List
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BUIP7T7Z4T3UHLXFWG6XIVDP4GYPD3AI/ Vendor Advisory Mailing List
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HVRDSJVZKMCXKKPP6PNR62T7RWZ3YSDZ/ Vendor Advisory Mailing List
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IGSLGKUAQTW5JPPZCMF5YPEYALLRUZZ6/ Vendor Advisory Mailing List
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PNNHZSZPG2E7NBMBNYPGHCFI4V4XRWNQ/ Vendor Advisory Mailing List
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RGS7JN6FZXUSTC2XKQHH27574XOULYYJ/ Vendor Advisory Mailing List
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SVYA42BLXUCIDLD35YIJPJSHDIADNYMP/ Vendor Advisory Mailing List
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TEXGOYGW7DBS3N2QSSQONZ4ENIRQEAPG/ Vendor Advisory Mailing List
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UQESRWMJCF4JEYJEAKLRM6CT55GLJAB7/ Vendor Advisory Mailing List
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZDZFMEKQTZ4L7RY46FCENWFB5MDT263R/ Vendor Advisory Mailing List
https://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2024q1/017430.html Mailing 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
https://lists.debian.org/debian-lts-announce/2024/09/msg00001.html Vendor Advisory Mailing List
https://lists.debian.org/debian-lts-announce/2024/11/msg00035.html Vendor Advisory Mailing List
https://lists.fedoraproject.org/archives/list/[email protected]/message/BUIP7T7Z4T3UHLXFWG6XIVDP4GYPD3AI/ Vendor Advisory Mailing List
https://lists.fedoraproject.org/archives/list/[email protected]/message/HVRDSJVZKMCXKKPP6PNR62T7RWZ3YSDZ/ Vendor Advisory Mailing List
https://lists.fedoraproject.org/archives/list/[email protected]/message/ZDZFMEKQTZ4L7RY46FCENWFB5MDT263R/ Vendor Advisory Mailing List
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