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Full vulnerability report · 2026
CVE-2026-21998High confidence

Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Optimizer)

Oracle Corporation · MySQL Server

4.9MediumCVSS 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.

Fix not verified
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 releaseSource packageVendor stateFixed versionEvidence
Ubuntu 24.04 LTSnoble · standard archivemysql-8.0Vendor fix publishedCanonical reports that a fixed source package version has been published. Repository candidate availability is not checked by BlackTree.8.0.46-0ubuntu0.24.04.2Canonical record ↗Source updated 4 Sept 2026
Optional official sources

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

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

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-2026-24295

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.

Fix not verified
01

What, why and how

Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Optimizer). Supported versions that are affected are 8.0.0-8.0.45, 8.4.0-8.4.8 and 9.0.0-9.6.0. Easily exploitable vulnerability allows high privileged attacker with network access via multiple protocols to compromise MySQL Server. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of MySQL Server. CVSS 3.1 Base Score 4.9 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H).

What

Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Optimizer). Supported versions that are affected are 8.0.0-8.0.45, 8.4.0-8.4.8 and 9.0.0-9.6.0. Easily exploitable vulnerability allows high privileged attacker with network access via multiple protocols to compromise MySQL Server. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of MySQL Server. CVSS 3.1 Base Score 4.9 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H).

Why

The product does not properly control the allocation and maintenance of a limited resource.

How

An attacker operating through a network path may attempt exploitation with elevated privileges. If successful, the issue may disrupt the affected service.

What

Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Optimizer). Supported versions that are affected are 8.0.0-8.0.45, 8.4.0-8.4.8 and 9.0.0-9.6.0. Easily exploitable vulnerability allows high privileged attacker with network access via multiple protocols to compromise MySQL Server. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of MySQL Server. CVSS 3.1 Base Score 4.9 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H).

Why

The product does not properly control the allocation and maintenance of a limited resource.

How

An attacker operating through a network path may attempt exploitation with elevated privileges. If successful, the issue may disrupt the affected service.

02

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 → Uncontrolled Resource Consumption → disrupt the affected service
Attack surface
Network
Privileges required
High: elevated access 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-400

CWE-400: Uncontrolled Resource Consumption. The product does not properly control the allocation and maintenance of a limited resource.

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:H/UI:N/S:U/C:N/I:N/A:H

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.PRHighPrivileges required: The attacker needs elevated or administrative privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
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.
NetworkDenial of serviceCWE-400
A

Official authority intelligence

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

BSI · German · WID-SEC-W-2026-2455Oracle Solaris Drittanbieterkomponenten: Mehrere Schwachstellen

Ein entfernter, anonymer oder authentisierter Angreifer kann mehrere Schwachstellen in verschiedenen Komponenten von Drittanbietern in Oracle Solaris ausnutzen, um einen nicht näher spezifizierten Angriff durchzuführen.

Official advisory
BSI · German · WID-SEC-W-2026-1199Oracle MySQL: Mehrere Schwachstellen

Ein entfernter, anonymer oder authentisierter Angreifer kann mehrere Schwachstellen in Oracle MySQL ausnutzen, um die Vertraulichkeit, Integrität und Verfügbarkeit zu gefährden.

Official advisory
CERT-FR · French · CERTFR-2026-AVI-0556Multiples vulnérabilités dans les produits VMware

cord?id=CVE-2026-2005 Référence CVE CVE-2026-2006 https://www.cve.org/CVERecord?id=CVE-2026-2006 Référence CVE CVE-2026-21441 https://www.cve.org/CVERecord?id=CVE-2026-21441 Référence CVE CVE-2026-21860 https://www.cve.org/CVERecord?id=CVE-2026-21860 Référence CVE CVE-2026-21936 https://www.cve.org/CVERecord?id=CVE-2026-21936 Référence CVE CVE-2026-21937 https://www.cve.org/CVERecord?id=CVE-2026-21937 Référence CVE CVE-2026-21948 https://www.cve.org/CVERecord?id=CVE-2026-21948 Référence CVE CVE-2026-21964 https://www.cve.org/CVERecord?id=CVE-2026-21964 Référence CVE CVE-2026-21968 https://www.cve.org/CVERecord?id=CVE-2026-21968 Référence CVE CVE-2026-21998 https://www.cve.org/CVERecord?id=CVE-2026-21998 Référence CVE CVE-2026-22001 https://www.cve.org/CVERecord?id=CVE-2026-22001 Référence CVE CVE-2026-22002 https://www.cve.org/CVERecord?id=CVE-2026-22002 Référence CVE CVE-2026-22004 https://www.cve.org/CVERecord?id=CVE-2026-22004 Référence CVE CVE-2026-22005 https://www.cve.org/CVERecord?id=CVE-2026-22005 Référence CVE CVE-2026-22009 https://www.cve.org/CVERecord?id=CVE-2026-22009 Référence CVE CVE-2026-22015 https://www.cve.org/CVERecord?id=CVE-2026-22015 Référence CVE CVE-2026-22017 https://www.cve.org/CVERecord?id=CVE-2026-22017 Référence CVE CVE-2026-22022 https://www.cve.org/CVERecord?id=

Official advisory
CERT-FR · French · CERTFR-2026-AVI-0503Multiples vulnérabilités dans les produits Microsoft

es Flux RSS des menaces et incidents Flux RSS des avis Flux RSS des indicateurs de compromission Flux RSS des durcissement et recommandations Flux RSS des bulletins d'actualité Premier Ministre S.G.D.S.N Agence nationale de la sécurité des systèmes d'information Paris, le 27 avril 2026 N° CERTFR-2026-AVI-0503 Affaire suivie par: CERT-FR Avis du CERT-FR Objet: Multiples vulnérabilités dans les produits Microsoft Gestion du document Référence CERTFR-2026-AVI-0503 Titre Multiples vulnérabilités dans les produits Microsoft Date de la première version 27 avril 2026 Date de la dernière version 27 avril 2026 Source(s) Bulletin de sécurité Microsoft CVE-2026-21998 du 23 avril 2026 Bulletin de sécurité Microsoft CVE-2026-22001 du 23 avril 2026 Bulletin de sécurité Microsoft CVE-2026-22002 du 23 avril 2026 Bulletin de sécurité Microsoft CVE-2026-22004 du 23 avril 2026 Bulletin de sécurité Microsoft CVE-2026-22005 du 23 avril 2026 Bulletin de sécurité Microsoft CVE-2026-22009 du 23 avril 2026 Bulletin de sécurité Microsoft CVE-2026-22015 du 23 avril 2026 Bulletin de sécurité Microsoft CVE-2026-22017 du 23 avril 2026 Bulletin de sécurité Microsoft CVE-2026-34267 du 23 avril 2026 Bulletin de sécurité Microsoft CVE-2026-34270 du 23 avril 2026 Bulletin de sécurité Microsoft CVE-2026-34271 du 23 avril 2026 Bu

Official advisory
CERT-FR · French · CERTFR-2026-AVI-0469Multiples vulnérabilités dans Oracle MySQL

Record?id=CVE-2025-5372 Référence CVE CVE-2025-5449 https://www.cve.org/CVERecord?id=CVE-2025-5449 Référence CVE CVE-2025-5987 https://www.cve.org/CVERecord?id=CVE-2025-5987 Référence CVE CVE-2025-66199 https://www.cve.org/CVERecord?id=CVE-2025-66199 Référence CVE CVE-2025-68160 https://www.cve.org/CVERecord?id=CVE-2025-68160 Référence CVE CVE-2025-69418 https://www.cve.org/CVERecord?id=CVE-2025-69418 Référence CVE CVE-2025-69419 https://www.cve.org/CVERecord?id=CVE-2025-69419 Référence CVE CVE-2025-69420 https://www.cve.org/CVERecord?id=CVE-2025-69420 Référence CVE CVE-2025-69421 https://www.cve.org/CVERecord?id=CVE-2025-69421 Référence CVE CVE-2026-21998 https://www.cve.org/CVERecord?id=CVE-2026-21998 Référence CVE CVE-2026-22001 https://www.cve.org/CVERecord?id=CVE-2026-22001 Référence CVE CVE-2026-22002 https://www.cve.org/CVERecord?id=CVE-2026-22002 Référence CVE CVE-2026-22004 https://www.cve.org/CVERecord?id=CVE-2026-22004 Référence CVE CVE-2026-22005 https://www.cve.org/CVERecord?id=CVE-2026-22005 Référence CVE CVE-2026-22009 https://www.cve.org/CVERecord?id=CVE-2026-22009 Référence CVE CVE-2026-22015 https://www.cve.org/CVERecord?id=CVE-2026-22015 Référence CVE CVE-2026-22017 https://www.cve.org/CVERecord?id=CVE-2026-22017 Référence CVE CVE-2026-22795 https://www.cve.org/CVERecord?id=

Official advisory
03

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.
Fix not verified
Affected
8.0.0 ≤ 8.0.45; 8.4.0 ≤ 8.4.8; 9.0.0 ≤ 9.6.0
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
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.
04

Evidence and provenance

Published 21 Apr 2026 · Last source change 22 Apr 2026, 14:03 UTC · CWE-400 · Uncontrolled Resource Consumption

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-2026-24295
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCISA ADP
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.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
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.
Free version - for non-commercial use only.CVE-2026-21998 · cve.blacktree.nl