CVE-2023-4408 | Parsing large DNS messages may cause excessive CPU load

The DNS message parsing code in `named` includes a section whose computational complexity is overly high. It does not cause problems for typical DNS traffic, but crafted queries and responses may cause excessive CPU load on the affected `named` instance by exploiting this flaw. This issue affects both authoritative servers and recursive resolvers. This issue affects BIND 9 versions 9.0.0 through 9.16.45, 9.18.0 through 9.18.21, 9.19.0 through 9.19.19, 9.9.3-S1 through 9.11.37-S1, 9.16.8-S1 through 9.16.45-S1, and 9.18.11-S1 through 9.18.21-S1.

Published: 2024-02-13 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-4408 is rated Moderate Risk (54.5/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.33%). EPSS rose +1.03% over the last day, indicating growing attacker interest. Review affected assets and schedule remediation.

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

Exploit prediction scoring system (EPSS) score for CVE-2023-4408

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 2026-06-15 0.29% 1.33% +1.03%
2 2026-03-05 0.24% 0.29% +0.05%
3 2026-01-18 — 0.24% —

Full EPSS history (21 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-4408

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]

Weakness enumeration for CVE-2023-4408

OS Trackers for CVE-2023-4408

vendor priority summary link
alpine — CVE-2023-4408: 1 source package rows (bind); 7 state rows across 7 repos (3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 7, open 0. https://security.alpinelinux.org/vuln/CVE-2023-4408
debian not yet assigned CVE-2023-4408 not yet assigned priority: Debian including 1 source packages (bind9), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2023-4408
redhat high — https://access.redhat.com/security/cve/CVE-2023-4408
suse high CVE-2023-4408 severity important: SUSE including 397 source package names (amazon/suse-sles-15-sp1-chost-byos-v20210304-hvm-ssd-x86_64, amazon/suse-sles-15-sp1-chost-byos-v20220127-hvm-ssd-x86_64, …), 1221 product×package rows across 220 product lines (HPE Helion OpenStack 8, Image SLES12-SP5-Azure-BYOS, … (220 product lines)): Fixed 931, Known Affected 195, Known Not Affected 95. https://www.suse.com/security/cve/CVE-2023-4408/
ubuntu medium CVE-2023-4408 medium priority: Ubuntu including 3 source packages (bind9, bind9-libs, isc-dhcp), 33 status rows across 11 suites (bionic, focal, jammy, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 8, released 8, ignored 6, needs-triage 6, not-affected 5. https://ubuntu.com/security/CVE-2023-4408

Affected software / configurations for CVE-2023-4408

Vendor Product Version Raw CPE
netapp ontap 9.14.1 cpe:2.3:a:netapp:ontap:9.14.1:*:*:*:*:*:*:*
netapp ontap 9.15.1 cpe:2.3:a:netapp:ontap:9.15.1:*:*:*:*:*:*:*
fedoraproject fedora 38 cpe:2.3:o:fedoraproject:fedora:38:*:*:*:*:*:*:*
fedoraproject fedora 39 cpe:2.3:o:fedoraproject:fedora:39:*:*:*:*:*:*:*
isc bind >= 9.0.0, <= 9.16.45 cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*
isc bind >= 9.18.0, <= 9.18.21 cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*
isc bind >= 9.19.0, <= 9.19.19 cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*
isc bind 9.9.3 cpe:2.3:a:isc:bind:9.9.3:s1:*:*:supported_preview:*:*:*
isc bind 9.16.8 cpe:2.3:a:isc:bind:9.16.8:s1:*:*:supported_preview:*:*:*
isc bind 9.16.11 cpe:2.3:a:isc:bind:9.16.11:s1:*:*:supported_preview:*:*:*
isc bind 9.16.12 cpe:2.3:a:isc:bind:9.16.12:s1:*:*:supported_preview:*:*:*
isc bind 9.16.13 cpe:2.3:a:isc:bind:9.16.13:s1:*:*:supported_preview:*:*:*
isc bind 9.16.14 cpe:2.3:a:isc:bind:9.16.14:s1:*:*:supported_preview:*:*:*
isc bind 9.16.21 cpe:2.3:a:isc:bind:9.16.21:s1:*:*:supported_preview:*:*:*
isc bind 9.16.32 cpe:2.3:a:isc:bind:9.16.32:s1:*:*:supported_preview:*:*:*
isc bind 9.16.36 cpe:2.3:a:isc:bind:9.16.36:s1:*:*:supported_preview:*:*:*
isc bind 9.16.43 cpe:2.3:a:isc:bind:9.16.43:s1:*:*:supported_preview:*:*:*
isc bind 9.18.0 cpe:2.3:a:isc:bind:9.18.0:s1:*:*:supported_preview:*:*:*
isc bind 9.18.11 cpe:2.3:a:isc:bind:9.18.11:s1:*:*:supported_preview:*:*:*
isc bind 9.18.18 cpe:2.3:a:isc:bind:9.18.18:s1:*:*:supported_preview:*:*:*

References for CVE-2023-4408

cvelogic Threat Intelligence