A use-after-return vulnerability exists in the named server when handling DNS queries signed with SIG(0). Using a specially-crafted DNS request, an attacker may be able to cause an ACL to improperly (mis)match an IP address. In a default-allow ACL (denying only specific IP addresses), this may lead to unauthorized access. Default-deny ACLs should fail-secure.
This issue affects BIND 9 versions 9.20.0 through 9.20.20, 9.21.0 through 9.21.19, and 9.20.9-S1 through 9.20.20-S1.
BIND 9 versions 9.18.0 through 9.18.46 and 9.18.11-S1 through 9.18.46-S1 are NOT affected.
CVE-2026-3591
Score 5.4 from GitHub Security Advisory published 2026-03-25. NVD baseline CVSS 5.4; sources differ by 0.0.
- Lower severity and no public exploit yet
A fix is available — apply it.
- CVSS v3
- 5.4
- EG Score
- 5.4(medium)
- EPSS
- 28.1%
- KEV
- Not listed
Published
March 25, 2026
Last Modified
May 21, 2026
References (3)
- security-officer@ischttps://downloads.isc.org/isc/bind9/9.20.21
- security-officer@ischttps://downloads.isc.org/isc/bind9/9.21.20
- security-officer@ischttps://kb.isc.org/docs/cve-2026-3591
Vendor Advisories for CVE-2026-3591(2)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Patch Availability(2)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| ubuntu | bind9-utils (1:9.20.11-1ubuntu2.2) @ questing | 2026-06-11 | ubuntu |
| redhat | bind-main-9.18.48-1.hum1 | 2026-04-07 | redhat |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Additional Vendor Advisories
(1)
Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.
Data Freshness Timeline
(refreshed 8× in last 7d / 34× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-08 15:15 UTCEPSS rescore
- 2026-07-07 13:46 UTCEPSS rescore
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- 2026-06-30 23:22 UTCEPSS rescore
- 2026-06-29 14:06 UTCEPSS rescore
- 2026-06-28 14:07 UTCEPSS rescore
- 2026-06-28 04:56 UTCEPSS rescore
- 2026-06-27 03:08 UTCEPSS rescore
- 2026-06-25 13:49 UTCEPSS rescore
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- 2026-06-23 21:33 UTCEPSS rescore
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- 2026-06-22 14:25 UTCEPSS rescore
- 2026-06-21 14:56 UTCEPSS rescore
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- 2026-06-19 19:25 UTCEPSS rescore
- 2026-06-18 17:52 UTCEPSS rescore
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- 2026-06-16 17:52 UTCEPSS rescore
- 2026-06-15 17:49 UTCEPSS rescore
- 2026-06-13 23:00 UTCEPSS rescore
- 2026-06-12 23:12 UTCEPSS rescore
- 2026-06-12 23:12 UTCEPSS rescore
- 2026-06-11 23:30 UTCEG score recompute
- 2026-06-11 23:30 UTCVendor advisory
- 2026-06-11 23:30 UTCGHSA enrichment
- 2026-06-11 14:00 UTCEPSS rescore
- 2026-06-10 22:18 UTCEPSS rescore
- 2026-06-10 17:48 UTCEG score recompute
- 2026-06-10 17:48 UTCVendor advisory
- 2026-06-10 17:48 UTCGHSA enrichment
- 2026-06-10 13:22 UTCEPSS rescore
- 2026-06-09 16:01 UTCEG score recompute
- 2026-06-09 16:01 UTCVendor advisory
- 2026-06-09 16:01 UTCGHSA enrichment
- 2026-06-08 14:17 UTCEPSS rescore
- 2026-06-08 14:17 UTCEPSS rescore
- 2026-06-08 14:14 UTCEG score recompute
- 2026-06-08 14:14 UTCVendor advisory
- 2026-06-08 14:14 UTCGHSA enrichment
- 2026-06-07 15:25 UTCEPSS rescore
- 2026-06-07 15:25 UTCEPSS rescore
- 2026-06-07 15:25 UTCEPSS rescore
- 2026-06-07 12:26 UTCEG score recompute
- 2026-06-07 12:26 UTCVendor advisory
- 2026-06-07 12:26 UTCGHSA enrichment
- 2026-06-06 13:47 UTCEPSS rescore
- 2026-06-06 13:47 UTCEPSS rescore
- 2026-06-05 22:47 UTCEPSS rescore
- 2026-06-05 22:47 UTCEPSS rescore
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- 2026-06-04 13:12 UTCEPSS rescore
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- 2026-06-01 13:52 UTCEPSS rescore
- 2026-06-01 13:52 UTCEPSS rescore
- 2026-06-01 13:51 UTCEPSS rescore
- 2026-05-31 22:30 UTCEPSS rescore
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- 2026-05-31 00:16 UTCEPSS rescore
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- 2026-05-31 00:16 UTCEPSS rescore
- 2026-05-29 13:44 UTCEPSS rescore
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- 2026-05-28 13:44 UTCEPSS rescore
- 2026-05-28 13:44 UTCEPSS rescore
- 2026-05-28 13:44 UTCEPSS rescore
- 2026-05-27 13:40 UTCEPSS rescore
- 2026-05-27 13:40 UTCEPSS rescore
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- 2026-05-26 13:44 UTCEPSS rescore
- 2026-05-26 07:18 UTCEPSS rescore
- 2026-05-26 07:18 UTCEPSS rescore
- 2026-05-21 16:42 UTCEG score recompute
- 2026-05-21 16:42 UTCVendor advisory
- 2026-05-21 16:42 UTCGHSA enrichment
Frequently asked(5)
What is CVE-2026-3591?
When was CVE-2026-3591 disclosed?
Is CVE-2026-3591 actively exploited?
What is the CVSS score of CVE-2026-3591?
How do I remediate CVE-2026-3591?
Dependency Blast Radius
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