CVE-2023-50868
Uncontrolled Resource Consumption
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
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.
Official description from the CVE record, published by mitre. Copyright © 1999-2026 The MITRE Corporation. See /security/cve/legal for the CVE license. View the record on cve.org
Key data
CVSS 3.1 High 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
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: High
Serious or total effect on the trustworthiness of data.
Availability impact: None
No effect on availability.
| 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 | High | Serious or total effect on the trustworthiness of data. |
| Availability impact | None | No effect on availability. |
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EPSS
- Score
- 0.74295 (74.3% probability)
- Percentile
- 99.5%
- Scores of
- Nov 10, 2026
- Model
- v2026.06.15
CISA assessment as of Feb 19, 2024
- Automatable
- yes
- Technical impact
- partial
Weakness (CWE)
- CWE-400Uncontrolled Resource Consumption
References
- nlnetlabs.nl/news/2024/Feb/13/unbound-1.19.1-released
- docs.powerdns.com/recursor/security-advisories/powerdns-adv…
- isc.org/blogs/2024-bind-security-release
- datatracker.ietf.org/doc/html/rfc5155
- kb.isc.org/docs/cve-2023-50868
- gitlab.nic.cz/knot/knot-resolver/-/releases/v5.7.1
- lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2024q1/01…
- access.redhat.com/security/cve/CVE-2023-50868
- bugzilla.suse.com/show_bug.cgi?id=1219826
- [oss-security] 20240216 Re: Unbound: disclosure of CVE-2023-50387 and CVE-2023-50868 DNSSEC validation vulnerabilities (openwall.com)mailing-list
- [oss-security] 20240216 Re: Unbound: disclosure of CVE-2023-50387 and CVE-2023-50868 DNSSEC validation vulnerabilities (openwall.com)mailing-list
- FEDORA-2024-2e26eccfcb (lists.fedoraproject.org)vendor-advisory
- FEDORA-2024-e24211eff0 (lists.fedoraproject.org)vendor-advisory
- FEDORA-2024-21310568fa (lists.fedoraproject.org)vendor-advisory
- [debian-lts-announce] 20240221 [SECURITY] [DLA 3736-1] unbound security update (lists.debian.org)mailing-list
- FEDORA-2024-b0f9656a76 (lists.fedoraproject.org)vendor-advisory
- FEDORA-2024-4e36df9dfd (lists.fedoraproject.org)vendor-advisory
- FEDORA-2024-499b9be35f (lists.fedoraproject.org)vendor-advisory
- FEDORA-2024-c36c448396 (lists.fedoraproject.org)vendor-advisory
- FEDORA-2024-c967c7d287 (lists.fedoraproject.org)vendor-advisory
- FEDORA-2024-e00eceb11c (lists.fedoraproject.org)vendor-advisory
- FEDORA-2024-fae88b73eb (lists.fedoraproject.org)vendor-advisory
- security.netapp.com/advisory/ntap-20240307-0008
- [debian-lts-announce] 20240517 [SECURITY] [DLA 3816-1] bind9 security update (lists.debian.org)mailing-list
- lists.debian.org/debian-lts-announce/2024/11/msg00035.html
- lists.debian.org/debian-lts-announce/2024/09/msg00001.html
- lists.fedoraproject.org/archives/list/package-announce@list…
- lists.fedoraproject.org/archives/list/package-announce@list…
- lists.fedoraproject.org/archives/list/package-announce@list…
Timeline
- ID reserved
- Record published
- Record last updated
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About CubePath
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, 19:50 UTC. Sources and licenses