Evidence used
- No CISA KEV confirmation is currently recorded.
- EPSS is 1.34% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2021
CVE-2021-21218High confidence
Uninitialized data in PDFium in Google Chrome prior to 90.0.4430.72 allowed a remote attacker to obtain potentially sensitive information from process memory via a crafted PDF file
Google · Chrome
5.5MediumCVSS 3.1
Scheduled
Fix not verifiedMedium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityMedium→Operational priority:Medium, unchanged from published severity.unchanged
Compensating controls
- Restrict local access and enforce least privilege on affected hosts.
- Monitor vendor guidance and exploitation sources for a material change.
Verification
- Confirm that the asset runs Google Chrome and falls inside the recorded affected range.
- Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Distribution package intelligence
7 package statesRelease-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.
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 release | Source package | Vendor state | Fixed version | Evidence |
|---|---|---|---|---|
| Alpine v3.23v3.23 · community | chromium | Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected. | 90.0.4430.72-r0 | Alpine Security Database ↗Source updated 11 Sep 2026 |
| Alpine v3.22v3.22 · community | chromium | Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected. | 90.0.4430.72-r0 | Alpine Security Database ↗Source updated 11 Sep 2026 |
| Alpine v3.21v3.21 · community | chromium | Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected. | 90.0.4430.72-r0 | Alpine Security Database ↗Source updated 19 Aug 2026 |
| Debian trixietrixie · source | chromium | Vendor fix publishedDebian records a fixed source-package version for this release. | 90.0.4430.72-1 | Debian Security Tracker ↗Source updated 6 Oct 2026 |
| Debian bookwormbookworm · source | chromium | Vendor fix publishedDebian records a fixed source-package version for this release. | 90.0.4430.72-1 | Debian Security Tracker ↗Source updated 6 Oct 2026 |
| Debian forkyforky · source | chromium | Vendor fix publishedDebian records a fixed source-package version for this release. | 90.0.4430.72-1 | Debian Security Tracker ↗Source updated 6 Oct 2026 |
| Debian sidsid · source | chromium | Vendor fix publishedDebian records a fixed source-package version for this release. | 90.0.4430.72-1 | Debian Security Tracker ↗Source updated 6 Oct 2026 |
Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.
Fix not verified01
What, why and how
Uninitialized data in PDFium in Google Chrome prior to 90.0.4430.72 allowed a remote attacker to obtain potentially sensitive information from process memory via a crafted PDF file.
What
Uninitialized data in PDFium in Google Chrome prior to 90.0.4430.72 allowed a remote attacker to obtain potentially sensitive information from process memory via a crafted PDF file.
Why
The product uses or accesses a resource that has not been initialized.
How
An attacker operating through local access may attempt exploitation without authentication after a user interaction. If successful, the issue may obtain information outside the intended access boundary.
What
Uninitialized data in PDFium in Google Chrome prior to 90.0.4430.72 allowed a remote attacker to obtain potentially sensitive information from process memory via a crafted PDF file.
Why
The product uses or accesses a resource that has not been initialized.
How
An attacker operating through local access may attempt exploitation without authentication after a user interaction. If successful, the issue may obtain information outside the intended access boundary.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.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 None recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.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
- local access → Use of Uninitialized Resource → obtain information outside the intended access boundary
- Attack surface
- Local
- 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-908 ↗
CWE-908: Use of Uninitialized Resource. The product uses or accesses a resource that has not been initialized.
- CVSS vector
?
CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity. CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:NCommon Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVLocalAttack vector: The attacker needs local access to the vulnerable system.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.CHighConfidentiality impact: A successful attack can cause a major loss.INoneIntegrity impact: No direct loss is represented by this metric.ANoneAvailability impact: No direct loss is represented by this metric.- Post-exploitation / living off the land
- The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.
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
- Chrome: unspecified < 90.0.4430.72
- 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. Limit untrusted access and use least privilege until authoritative guidance is available.
04
Evidence and provenance
Published 26 Apr 2021 · Last source change 3 Aug 2024, 18:01 UTC · CWE-908 · Use of Uninitialized Resource
CVE recordCVE.org · 5.1
CVSS sourceNIST NVD
EPSS source FIRST · tracked since 2026-08-14
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2021-8609
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceNIST NVD
NVD statusNVD modified after enrichment
Core structured fields are present and their contributing authorities are shown above.
Material change intelligence
View recent updates ↗What changed after publication
No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.
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.