CVE-2023-50868: Isc Bind denial of service (CVSS 7.5)

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 breakdown

Attack vectorNetwork

Attack complexityLow

Privileges requiredNone

User interactionNone

ScopeUnchanged

ConfidentialityNone

IntegrityNone

AvailabilityHigh

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

Affected products

Isc Bind≥ 9.0.0 < 9.16.48 · ≥ 9.18.0 < 9.18.24 · ≥ 9.19.0 < 9.19.21 · ≥ 9.18.11 < 9.18.24

Netapp Active Iq Unified Managerall versions

Netapp Hci Baseboard Management Controllerall versions

Powerdns Recursor≥ 4.9.0 < 4.9.3 · ≥ 5.0.0 < 5.0.2 · < 4.8.5

Debian Linux10.0 · 11.0

Fedoraproject Fedora38 · 39

Netapp Bootstrap OSall versions

Redhat Enterprise Linux6.0 · 7.0 · 8.0 · 8.2

Remediation

Fixed in

Isc Bind≥ 9.16.48

Powerdns Recursor≥ 4.9.3

Patch & vendor advisories

References

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.htmlVendor AdvisoryMailing List
https://lists.debian.org/debian-lts-announce/2024/05/msg00011.htmlVendor AdvisoryMailing List
https://lists.debian.org/debian-lts-announce/2024/09/msg00001.htmlVendor AdvisoryMailing List
https://lists.debian.org/debian-lts-announce/2024/11/msg00035.htmlVendor AdvisoryMailing List

and 19 more references

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

Frequently asked

Is CVE-2023-50868 being actively exploited?

CVE-2023-50868 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 73.7%.

How severe is CVE-2023-50868?

CVE-2023-50868 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 73.7% probability of exploitation.

Which products are affected by CVE-2023-50868?

Affected products include Isc Bind, Netapp Active Iq Unified Manager, Netapp Hci Baseboard Management Controller, Powerdns Recursor, Debian Linux, and 3 more.

How do I fix CVE-2023-50868?

Upgrade affected software to a fixed version, for example Isc Bind 9.16.48, Powerdns Recursor 4.9.3 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2023-50868 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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