CVE-2026-3593

Heap use-after-free vulnerability in BIND 9 DNS-over-HTTPS implementation

At a glance

Severity: HIGH 7.4
EPSS: EPSS 1.54 % · percentile 75 (2026-10-27)
State: PUBLISHED
Published: 2026-05-20
Updated: 2026-09-01
Assigner: isc
NVD status: Modified

Description

A use-after-free vulnerability exists within the DNS-over-HTTPS implementation. This issue affects BIND 9 versions 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, and 9.20.9-S1 through 9.20.22-S1. BIND 9 versions 9.18.0 through 9.18.48 and 9.18.11-S1 through 9.18.48-S1 are NOT affected.

Scores

Version	Score	Vector	Scored by
CVSS 3.1	HIGH 7.4	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H	isc
CVSS 3.1	HIGH 7.4	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H	redhat-SADP
CVSS 3.1	HIGH 7.4	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H	NVD · security-officer@isc.org (Secondary)
CVSS 3.1	CRITICAL 9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H	NVD · nvd@nist.gov (Primary)
CVSS 3.1	HIGH 7.4	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H	NVD · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c (Secondary)

Weaknesses (CWE)

European references

ENISA EUVD · EUVD-2026-31108
GCVE · GCVE-0-2026-3593

CERT-FR advisories

CERTFR-2026-AVI-0618 — Multiples vulnérabilités dans ISC BIND · cert.ssi.gouv.fr

Affected configurations (NVD CPE)

cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:* ≥ 9.20.0 < 9.20.23
cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:* ≥ 9.21.0 < 9.21.22

Affected products

Product	Versions
ISC · BIND 9	affected 9.20.0 ≤ 9.20.22 ; affected 9.21.0 ≤ 9.21.21 ; affected 9.20.9-S1 ≤ 9.20.22-S1 ; unaffected 9.18.0 ≤ 9.18.48 ; unaffected 9.18.11-S1 ≤ 9.18.48-S1

References

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)	Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD