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Full vulnerability report · 2026
CVE-2026-66798High confidence

Microsoft Edge (Chromium-based) Remote Code Execution Vulnerability

Microsoft · Microsoft Edge (Chromium-based)

4.3MediumCVSS 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
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-2026-66798 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitycluster-backup-operator: cluster-backup-operator: Restore.spec.hooks passed verbatim to Velero Restore — arbitrary command execution in restored pods
24 fixed

The vendor explicitly identifies these products or versions as containing the fix.

  • registry.redhat.io/rhacm2/cluster-backup-rhel9-operator@sha256:44ddf9fae94ac2f4e74c35433a612c8a0dabf531384f2974a8c4872cde0efaa1_arm64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.11
  • registry.redhat.io/rhacm2/cluster-backup-rhel9-operator@sha256:5291e93f95e8350e361470eec8cd6cac6e697aa712fb061bfa780981a47cb17b_ppc64le as a component of Red Hat Advanced Cluster Management for Kubernetes 2.11
  • registry.redhat.io/rhacm2/cluster-backup-rhel9-operator@sha256:a1af35a23b6ed7aeb297bb59d6ffa84505769c36727c6628667dddd4d87569ad_s390x as a component of Red Hat Advanced Cluster Management for Kubernetes 2.11
  • registry.redhat.io/rhacm2/cluster-backup-rhel9-operator@sha256:e934fad530ced942202a8e893c1ee4a931856709a46a9d711e67779cbf9d48ee_amd64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.11
  • registry.redhat.io/rhacm2/cluster-backup-rhel9-operator@sha256:016023aaab9f3476900a3e7bf2126875500dd171834bad8c395f42a2baae795e_ppc64le as a component of Red Hat Advanced Cluster Management for Kubernetes 2.13
  • registry.redhat.io/rhacm2/cluster-backup-rhel9-operator@sha256:4641f23fc762a798ea7a94e85c44fbf21f37fb8c74d93d9f39c4fe120fd8704a_arm64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.13
  • registry.redhat.io/rhacm2/cluster-backup-rhel9-operator@sha256:dd29bb691d5495ef504883b012248b03a4d8109000ba85dc470b0acb280aab40_s390x as a component of Red Hat Advanced Cluster Management for Kubernetes 2.13
  • registry.redhat.io/rhacm2/cluster-backup-rhel9-operator@sha256:f04d7d5454141691568e02f461bdca9bc58cc07f33244caf4f1caf27cd1d5866_amd64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.13
  • registry.redhat.io/rhacm2/cluster-backup-rhel9-operator@sha256:04fe2d4880d42890325ff697c84bd413218a9fd7f316c4dd195eb307ee2ae859_arm64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.14
  • registry.redhat.io/rhacm2/cluster-backup-rhel9-operator@sha256:3ffb54a51d08d77a3340914bac096cb31dc71145f681a9bcd311f1c38e4256a1_amd64 as a component of Red Hat Advanced Cluster Management for Kubernetes 2.14
  • registry.redhat.io/rhacm2/cluster-backup-rhel9-operator@sha256:b1b9c8a2641af71bc376784ad4ee622e116529a512e1a619a227fc8a19bd0af2_ppc64le as a component of Red Hat Advanced Cluster Management for Kubernetes 2.14
  • registry.redhat.io/rhacm2/cluster-backup-rhel9-operator@sha256:ffa6981a04f2439051744797f933da5221f7a96c46998188014e90b999a3ffd3_s390x as a component of Red Hat Advanced Cluster Management for Kubernetes 2.14
Summary
A flaw was found in cluster-backup-operator. A namespace administrator in open-cluster-management-backup can create a Restore Custom Resource (CR) with malicious hooks. These hooks allow the execution of arbitrary commands within any matching restored pod, leading to the exfiltration of ServiceAccount tokens. This bypasses normal access controls, granting the attacker unauthorized execution access to pods and their associated Service Accounts.
Remediation
Before you apply this update, make sure all previously released errata that are relevant to your system are applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
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-2026-67851

No EUVD known-exploited evidence

Use after free in Microsoft Edge (Chromium-based) allows an unauthorized attacker to execute code over a network.

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
4.3 · CVSS 3.1
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
01

What, why and how

Use after free in Microsoft Edge (Chromium-based) allows an unauthorized attacker to execute code over a network.

What

Use after free in Microsoft Edge (Chromium-based) allows an unauthorized attacker to execute code over a network.

Why

The program can continue using memory after it has been released, producing unsafe and attacker-influenceable behaviour.

How

An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may execute code or commands in the affected security context.

What

Use after free in Microsoft Edge (Chromium-based) allows an unauthorized attacker to execute code over a network.

Why

The program can continue using memory after it has been released, producing unsafe and attacker-influenceable behaviour.

How

An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may execute code or commands in the affected security context.

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 → Use After Free → execute code or commands in the affected security context
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
Required interaction required
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-416 ↗

CWE-416: Use After Free. The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

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:N/UI:R/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C

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.PRNonePrivileges required: The attacker does not need an account or existing privileges.UIRequiredUser interaction: Another user must perform an action for exploitation to succeed.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.ALowAvailability impact: A successful attack can cause a limited loss.
Post-exploitation / living off the land
After compromise, an attacker may use built-in shells, scripting engines, scheduled tasks and native network utilities for discovery, persistence or movement. This is a plausible LoTL path, not evidence that it has occurred for every attack.
NetworkUnauthenticatedRemote code executionCWE-416
A

Official authority intelligence

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

ENISA EUVD · EUVD-2026-67851Official EUVD mapping

Use after free in Microsoft Edge (Chromium-based) allows an unauthorized attacker to execute code over a network.

Official EUVD record ↗
BSI · German · WID-SEC-2026-3085Microsoft Edge: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Microsoft Edge ausnutzen, um beliebigen Code auszuführen, Sicherheitsmaßnahmen zu umgehen, Spoofing-Angriffe durchzuführen, Daten zu manipulieren oder offenzulegen oder einen Denial-of-Service-Zustand herbeizuführen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260902Security Bulletin 2 Sept 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 2 Sept 2026, published on 2 September 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-1096Multiples vulnérabilités dans Microsoft Edge

ormation Paris, le 31 août 2026 N° CERTFR-2026-AVI-1096 Affaire suivie par: CERT-FR Avis du CERT-FR Objet: Multiples vulnérabilités dans Microsoft Edge Gestion du document Référence CERTFR-2026-AVI-1096 Titre Multiples vulnérabilités dans Microsoft Edge Date de la première version 31 août 2026 Date de la dernière version 31 août 2026 Source(s) Bulletin de sécurité Microsoft Edge CVE-2026-58616 du 28 août 2026 Bulletin de sécurité Microsoft Edge CVE-2026-62904 du 28 août 2026 Bulletin de sécurité Microsoft Edge CVE-2026-66323 du 28 août 2026 Bulletin de sécurité Microsoft Edge CVE-2026-66324 du 28 août 2026 Bulletin de sécurité Microsoft Edge CVE-2026-66798 du 28 août 2026 Bulletin de sécurité Microsoft Edge CVE-2026-70309 du 28 août 2026 Bulletin de sécurité Microsoft Edge CVE-2026-70331 du 28 août 2026 Bulletin de sécurité Microsoft Edge CVE-2026-72984 du 28 août 2026 Bulletin de sécurité Microsoft Edge CVE-2026-78891 du 28 août 2026 Bulletin de sécurité Microsoft Edge CVE-2026-78892 du 28 août 2026 Bulletin de sécurité Microsoft Edge CVE-2026-78893 du 28 août 2026 Bulletin de sécurité Microsoft Edge CVE-2026-78894 du 28 août 2026 Bulletin de sécurité Microsoft Edge CVE-2026-78895 du 28 août 2026 Bulletin de sécurité Microsoft Edge CVE-2026-78896 du 28 août 2026 Bulletin de sécurité Microsoft

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-031289マイクロソフトのMicrosoft Edge Chromiumにおける解放済みメモリの使用に関する脆弱性

Microsoft Edge（Chromiumベース）におけるUse after freeの脆弱性により、不正な攻撃者がネットワークを介してコードを実行できる可能性があります。

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.
Patch available
Affected
Microsoft Edge (Chromium-based): 1.0.0.0 < 152.0.4191.53
Fixed
Action
Before you apply this update, make sure all previously released errata that are relevant to your system are applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
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 28 Aug 2026 · Last source change 29 Aug 2026, 16:24 UTC · CWE-416 · Use After Free

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 2026-08-29
European sourceENISA EUVD · EUVD-2026-67851
Product sourceCNA
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceOther authority
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 ↗
  1. Affected versionsThe structured affected or fixed version information changed.
    Before
    Microsoft Edge (Chromium-based): -; Microsoft Edge for Android: 1.0.0.0 < 152.0.4191.52; Microsoft Edge for iOS: 1.0.0.0 < 152.0.4191.52; Microsoft Edge for Linux: 1.0.0 < 152.0.4191.52; Microsoft Edge for MAC: 1.0.0.0 < 152.0.4191.52; Microsoft Edge for Windows: 1.0.0.0 < 152.0.4191.52 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    Microsoft Edge (Chromium-based): 1.0.0.0 < 152.0.4191.53 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    CNA ↗
  2. Affected versionsThe structured affected or fixed version information changed.
    Before
    -; 1.0.0.0 < 152.0.4191.52; 1.0.0 < 152.0.4191.52 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    Microsoft Edge (Chromium-based): -; Microsoft Edge for Android: 1.0.0.0 < 152.0.4191.52; Microsoft Edge for iOS: 1.0.0.0 < 152.0.4191.52; Microsoft Edge for Linux: 1.0.0 < 152.0.4191.52; Microsoft Edge for MAC: 1.0.0.0 < 152.0.4191.52; Microsoft Edge for Windows: 1.0.0.0 < 152.0.4191.52 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    CNA ↗
  3. Affected versionsThe structured affected or fixed version information changed.
    Before
    1.0.0.0 < 152.0.4191.53 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    -; 1.0.0.0 < 152.0.4191.52; 1.0.0 < 152.0.4191.52 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    CNA ↗
  4. Vendor guidanceAuthoritative vendor guidance changed from no authoritative guidance recorded to vendor advisory.
    Before
    no authoritative guidance recorded
    After
    vendor advisory
    secure@microsoft.com ↗
  5. ENISA EUVD mappingEUVD-2026-67851 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-67851"}
    ENISA EUVD ↗
  6. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2026-67851↗Vendor CSAF · Red Hat Product Security↗CVE authority or vendor 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.
Free version - for non-commercial use only.CVE-2026-66798 · cve.blacktree.nl