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Full vulnerability report · 2021
CVE-2021-30533High confidence

Google Chromium PopupBlocker Security Bypass Vulnerability

Google · Chromium PopupBlocker

6.5MediumCVSS 3.1
Recommended action
Patch now

CISA confirms exploitation in the wild and lists 2022-07-18 as the remediation due date.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Critical, raised 2 bands.upgradedsince 27 Jun 2022

Evidence used

  • CISA confirms exploitation in the wild.
  • A structured source references public exploit or proof-of-concept material.
  • EPSS is 16.74% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs Google Chromium PopupBlocker and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 3 daysRemediation target: Within 90 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Distribution package intelligence

Release-specific package status

Alpine, Debian findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.

10 package states
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.

Distribution releaseSource packageVendor stateFixed versionEvidence
Alpine v3.23v3.23 · communitychromiumVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.91.0.4472.77-r0Alpine Security Database ↗Source updated 11 Sep 2026
Alpine v3.23v3.23 · communityqt5-qtwebengineVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.5.15.3_git20210510-r4Alpine Security Database ↗Source updated 11 Sep 2026
Alpine v3.22v3.22 · communitychromiumVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.91.0.4472.77-r0Alpine Security Database ↗Source updated 11 Sep 2026
Alpine v3.22v3.22 · communityqt5-qtwebengineVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.5.15.3_git20210510-r4Alpine Security Database ↗Source updated 11 Sep 2026
Alpine v3.21v3.21 · communitychromiumVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.91.0.4472.77-r0Alpine Security Database ↗Source updated 19 Aug 2026
Alpine v3.21v3.21 · communityqt5-qtwebengineVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.5.15.3_git20210510-r4Alpine Security Database ↗Source updated 19 Aug 2026
Debian trixietrixie · sourcechromiumVendor fix publishedDebian records a fixed source-package version for this release.93.0.4577.82-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian bookwormbookworm · sourcechromiumVendor fix publishedDebian records a fixed source-package version for this release.93.0.4577.82-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian forkyforky · sourcechromiumVendor fix publishedDebian records a fixed source-package version for this release.93.0.4577.82-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian sidsid · sourcechromiumVendor fix publishedDebian records a fixed source-package version for this release.93.0.4577.82-1Debian Security Tracker ↗Source updated 6 Oct 2026
Optional official sources

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

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

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-2021-17454

CISA KEV mirrored by ENISA

Insufficient policy enforcement in PopupBlocker in Google Chrome prior to 91.0.4472.77 allowed a remote attacker to bypass navigation restrictions via a crafted iframe.

EUVD state
Present in the current official mapping
Known exploitation
Recorded by ENISA since 27 Jun 2022. Evidence sources: cisa_kev.
ENISA score
6.5 · CVSS 3.1
Advisory evidence
4 linked advisory records
Explicit mitigation evidence

Only statements that explicitly mention a fix, patch, update, workaround or mitigation are shown here.

  • csaf_opensuse · openSUSE-SU-2021:0840-1Security update for chromium
  • csaf_opensuse · openSUSE-SU-2021:0825-1Security update for chromium
Recommended actionPatch now

CISA confirms exploitation in the wild and lists 2022-07-18 as the remediation due date.

Patch available
01

What, why and how

Google Chromium PopupBlocker contains an insufficient policy enforcement vulnerability that allows a remote attacker to bypass navigation restrictions via a crafted iframe. This vulnerability could affect multiple web browsers that utilize Chromium, including, but not limited to, Google Chrome, Microsoft Edge, and Opera.

What

Google Chromium PopupBlocker contains an insufficient policy enforcement vulnerability that allows a remote attacker to bypass navigation restrictions via a crafted iframe. This vulnerability could affect multiple web browsers that utilize Chromium, including, but not limited to, Google Chrome, Microsoft Edge, and Opera.

Why

The application performs an authorisation check, but it does not correctly enforce the required permission boundary.

How

An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Google Chromium PopupBlocker contains an insufficient policy enforcement vulnerability that allows a remote attacker to bypass navigation restrictions via a crafted iframe. This vulnerability could affect multiple web browsers that utilize Chromium, including, but not limited to, Google Chrome, Microsoft Edge, and Opera.

Why

The application performs an authorisation check, but it does not correctly enforce the required permission boundary.

How

An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

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.
Confirmed in the wild

CISA added this CVE to its Known Exploited Vulnerabilities catalogue on 2022-06-27.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Reference recorded

A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.

Likely attack path
a network path → Incorrect Authorization → cause the confidentiality, integrity or availability impact described by the vendor
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-863 ↗

CWE-863: Incorrect Authorization. The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

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:H/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.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.IHighIntegrity impact: A successful attack can cause a major 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.
NetworkUnauthenticatedCWE-863CISA KEVPublic exploit reference
A

Official authority intelligence

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

ENISA EUVD · EUVD-2021-17454Known-exploited evidence recorded

Insufficient policy enforcement in PopupBlocker in Google Chrome prior to 91.0.4472.77 allowed a remote attacker to bypass navigation restrictions via a crafted iframe.

Official EUVD record ↗
Cyber Security Agency of Singapore · English · CSA-SB-20210609Security Bulletin 09 Jun 2021

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 09 Jun 2021, published on 9 June 2021. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2021-AVI-414Multiples vulnérabilités dans Microsoft Edge

d?id=CVE-2021-30524 Référence CVE CVE-2021-30525 https://www.cve.org/CVERecord?id=CVE-2021-30525 Référence CVE CVE-2021-30526 https://www.cve.org/CVERecord?id=CVE-2021-30526 Référence CVE CVE-2021-30527 https://www.cve.org/CVERecord?id=CVE-2021-30527 Référence CVE CVE-2021-30528 https://www.cve.org/CVERecord?id=CVE-2021-30528 Référence CVE CVE-2021-30529 https://www.cve.org/CVERecord?id=CVE-2021-30529 Référence CVE CVE-2021-30530 https://www.cve.org/CVERecord?id=CVE-2021-30530 Référence CVE CVE-2021-30531 https://www.cve.org/CVERecord?id=CVE-2021-30531 Référence CVE CVE-2021-30532 https://www.cve.org/CVERecord?id=CVE-2021-30532 Référence CVE CVE-2021-30533 https://www.cve.org/CVERecord?id=CVE-2021-30533 Référence CVE CVE-2021-30534 https://www.cve.org/CVERecord?id=CVE-2021-30534 Référence CVE CVE-2021-30535 https://www.cve.org/CVERecord?id=CVE-2021-30535 Référence CVE CVE-2021-30536 https://www.cve.org/CVERecord?id=CVE-2021-30536 Référence CVE CVE-2021-30537 https://www.cve.org/CVERecord?id=CVE-2021-30537 Référence CVE CVE-2021-30538 https://www.cve.org/CVERecord?id=CVE-2021-30538 Référence CVE CVE-2021-30539 https://www.cve.org/CVERecord?id=CVE-2021-30539 Référence CVE CVE-2021-30540 https://www.cve.org/CVERecord?id=CVE-2021-30540 Référence CVE CVE-2021-31937 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2021-AVI-404Multiples vulnérabilités dans Google Chrome

d?id=CVE-2021-30524 Référence CVE CVE-2021-30525 https://www.cve.org/CVERecord?id=CVE-2021-30525 Référence CVE CVE-2021-30526 https://www.cve.org/CVERecord?id=CVE-2021-30526 Référence CVE CVE-2021-30527 https://www.cve.org/CVERecord?id=CVE-2021-30527 Référence CVE CVE-2021-30528 https://www.cve.org/CVERecord?id=CVE-2021-30528 Référence CVE CVE-2021-30529 https://www.cve.org/CVERecord?id=CVE-2021-30529 Référence CVE CVE-2021-30530 https://www.cve.org/CVERecord?id=CVE-2021-30530 Référence CVE CVE-2021-30531 https://www.cve.org/CVERecord?id=CVE-2021-30531 Référence CVE CVE-2021-30532 https://www.cve.org/CVERecord?id=CVE-2021-30532 Référence CVE CVE-2021-30533 https://www.cve.org/CVERecord?id=CVE-2021-30533 Référence CVE CVE-2021-30534 https://www.cve.org/CVERecord?id=CVE-2021-30534 Référence CVE CVE-2021-30535 https://www.cve.org/CVERecord?id=CVE-2021-30535 Référence CVE CVE-2021-30536 https://www.cve.org/CVERecord?id=CVE-2021-30536 Référence CVE CVE-2021-30537 https://www.cve.org/CVERecord?id=CVE-2021-30537 Référence CVE CVE-2021-30538 https://www.cve.org/CVERecord?id=CVE-2021-30538 Référence CVE CVE-2021-30539 https://www.cve.org/CVERecord?id=CVE-2021-30539 Référence CVE CVE-2021-30540 https://www.cve.org/CVERecord?id=CVE-2021-30540 Gestion détaillée du document le 26 mai 2021 Version initiale

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2021-007700Google Chrome における不正な認証に関する脆弱性

Google Chrome には、不正な認証に関する脆弱性が存在します。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-5649현재 악용되고 있는 Exploit(Update. 2022-06-27)

Insufficient policy enforcement in the PopupBlocker for Chromium allows an attacker to remotely bypass security mechanisms. This vulnerability impacts web browsers using Chromium such as Chrome and Edge.

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
Chrome: unspecified < 91.0.4472.77
Fixed
An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
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 7 Jun 2021 · Last source change 21 Oct 2025, 23:25 UTC · CWE-863 · Incorrect Authorization

CVE recordCVE.org · 5.1
CVSS sourceNIST NVD
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-2021-17454
Product sourceCISA KEV
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 ↗
  1. Affected versionsThe structured affected or fixed version information changed.
    Before
    unspecified < 91.0.4472.77 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    After
    Chrome: unspecified < 91.0.4472.77 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Added to CISA KEV
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2021-17454↗CISA KEV record↗CVE authority or vendor reference↗Public exploit 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-2021-30533 · cve.blacktree.nl