BlackTreeIndependent security intelligence

Full vulnerability report · 2026

CVE-2026-3591High confidence

A stack use-after-return flaw in SIG(0) handling code may enable ACL bypass

ISC · BIND 9

5.4MediumCVSS 3.1

Recommended action

Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available

Distribution package intelligence

Ubuntu vendor package status

Canonical’s release and source-package findings are shown separately from local repository availability.

1 package state

Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Ubuntu release	Source package	Vendor state	Fixed version	Evidence
Ubuntu 24.04 LTSnoble · standard archive	`isc-dhcp`	Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.	`Not published in this feed`	Canonical record ↗Source updated 8 Sept 2026

Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current

CVE-2026-3591 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitybind: BIND: Unauthorized access due to use-after-return vulnerability in DNS query handling

9 known affected

The vendor explicitly identifies these products as affected by this CVE.

bind as a component of Red Hat Enterprise Linux 10
bind-chroot as a component of Red Hat Enterprise Linux 10
bind-devel as a component of Red Hat Enterprise Linux 10
bind-dnssec-utils as a component of Red Hat Enterprise Linux 10
bind-doc as a component of Red Hat Enterprise Linux 10
bind-libs as a component of Red Hat Enterprise Linux 10
bind-license as a component of Red Hat Enterprise Linux 10
bind-utils as a component of Red Hat Enterprise Linux 10
bind.src as a component of Red Hat Enterprise Linux 10

Summary: A flaw was found in BIND, specifically in the named server's handling of DNS queries signed with SIG(0). A remote attacker could exploit this use-after-return vulnerability by sending a specially-crafted DNS request. This could cause an Access Control List (ACL) to improperly match an IP address, potentially leading to unauthorized access to resources.
Remediation: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current

ENISA EUVD identifier

EUVD-2026-15413

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state: Present in the current official mapping
Known exploitation: Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score: Not supplied in the stored EUVD record
Advisory evidence: No linked advisory details stored yet

Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available

What, why and how

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.

What

Why

A function returns the address of a stack variable, which will cause unintended program behavior, typically in the form of a crash.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Why

A function returns the address of a stack variable, which will cause unintended program behavior, typically in the form of a crash.

How

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path: a network path → Return of Stack Variable Address → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface: Network
Privileges required: Low: a basic authenticated account is required
User interaction: None
Attack complexity: Low: no specialised conditions are recorded
Security boundary: Unchanged: impact remains within the vulnerable component's security authority
Weakness ? CWE means Common Weakness Enumeration: a standard category for the underlying weakness.: CWE-562 ↗
CWE-562: Return of Stack Variable Address. A function returns the address of a stack variable, which will cause unintended program behavior, typically in the form of a crash.
CVSS vector ? CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CLowConfidentiality impact: A successful attack can cause a limited loss.ILowIntegrity impact: A successful attack can cause a limited loss.ANoneAvailability impact: No direct loss is represented by this metric.
Post-exploitation / living off the land: No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.

NetworkCWE-562

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-15413Official EUVD mapping

0 linked advisory records.

Official EUVD record

BSI · German · WID-SEC-W-2026-0863Internet Systems Consortium BIND: Mehrere Schwachstellen

Ein entfernter, anonymer oder authentisierter Angreifer kann mehrere Schwachstellen in Internet Systems Consortium BIND ausnutzen, um einen Denial of Service Angriff durchzuführen oder Sicherheitsmaßnahmen zu umgehen.

Official advisory

CERT-FR · French · CERTFR-2026-AVI-0386Multiples vulnérabilités dans les produits Microsoft

De multiples vulnérabilités ont été découvertes dans les produits Microsoft. Elles permettent à un attaquant de provoquer un problème de sécurité non spécifié par l'éditeur.

Official advisory

CERT-FR · French · CERTFR-2026-AVI-0360Multiples vulnérabilités dans ISC BIND

De multiples vulnérabilités ont été découvertes dans ISC BIND. Elles permettent à un attaquant de provoquer un déni de service à distance, une atteinte à la confidentialité des données et un contournement de la politique de sécurité.

Official advisory

Patch and workaround

Operational remediation based on structured source evidence.

Status ? Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.: Patch available
Affected: bind as a component of Red Hat Enterprise Linux 10; bind-chroot as a component of Red Hat Enterprise Linux 10; bind-devel as a component of Red Hat Enterprise Linux 10; bind-dnssec-utils as a component of Red Hat Enterprise Linux 10; bind-doc as a component of Red Hat Enterprise Linux 10; bind-libs as a component of Red Hat Enterprise Linux 10; bind-license as a component of Red Hat Enterprise Linux 10; bind-utils as a component of Red Hat Enterprise Linux 10; bind.src as a component of Red Hat Enterprise Linux 10
Fixed: bind-main@aarch64 as a component of Red Hat Hardened Images; bind-main@noarch as a component of Red Hat Hardened Images; bind-main@src as a component of Red Hat Hardened Images; bind-main@x86_64 as a component of Red Hat Hardened Images
Action: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/
Workaround: No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.

Evidence and provenance

Published 25 Mar 2026 · Last source change 25 Mar 2026, 14:13 UTC · CWE-562 · Return of Stack Variable Address

CVE recordCVE.org · 5.2

CVSS sourceCNA

EPSS source

The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.

FIRST · tracked since 2026-08-14

European sourceENISA EUVD · EUVD-2026-15413

Product sourceVendor CSAF · Red Hat Product Security

Remediation sourceVendor CSAF · Red Hat Product Security

CWE sourceCNA

NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

2026-03-25CVE published

2026-03-25Fixed release or patch reference recorded

ENISA EUVD · EUVD-2026-15413↗Vendor CSAF · Red Hat Product Security↗CVE authority or vendor reference↗Patch or update reference↗Patch or update reference↗Official CVE record (CNA and ADP data)↗NVD record↗

Technical terms and abbreviations used in this report

CVE: Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS: Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS: Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE: Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA: CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP: Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD: National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT: A computer security incident response team that publishes warnings or coordinates incident response.
PoC: Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF: Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL: Living off the land: abuse of legitimate tools or system functions during an attack.

A stack use-after-return flaw in SIG(0) handling code may enable ACL bypass

National CERT insights ?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

EUVD-2026-15413

What, why and how

Exploit reality and attack path

Official authority intelligence

Patch and workaround

Evidence and provenance

National CERT insights
?
CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.