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Full vulnerability report · 2021
CVE-2021-1817High confidence

A memory corruption issue was addressed with improved state management

Apple · iOS and iPadOS

8.8HighCVSS 3.1
Recommended action
Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

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 archiveqtwebkit-opensource-srcUnder evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical 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-2021-7281

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 actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Fix not verified
01

What, why and how

A memory corruption issue was addressed with improved state management. This issue is fixed in macOS Big Sur 11.3, iOS 14.5 and iPadOS 14.5, watchOS 7.4, tvOS 14.5. Processing maliciously crafted web content may lead to arbitrary code execution.

What

A memory corruption issue was addressed with improved state management. This issue is fixed in macOS Big Sur 11.3, iOS 14.5 and iPadOS 14.5, watchOS 7.4, tvOS 14.5. Processing maliciously crafted web content may lead to arbitrary code execution.

Why

A bounds error lets data be written beyond the intended memory region, potentially corrupting control data.

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

A memory corruption issue was addressed with improved state management. This issue is fixed in macOS Big Sur 11.3, iOS 14.5 and iPadOS 14.5, watchOS 7.4, tvOS 14.5. Processing maliciously crafted web content may lead to arbitrary code execution.

Why

A bounds error lets data be written beyond the intended memory region, potentially corrupting control data.

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 → Out-of-bounds Write → 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-787 ↗

CWE-787: Out-of-bounds Write. The product writes data past the end, or before the beginning, of the intended buffer.

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:H/I:H/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.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.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major 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-787
A

Official authority intelligence

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

CERT-FR · French · CERTFR-2021-AVI-791Multiples vulnérabilités dans les produits IBM

.cve.org/CVERecord?id=CVE-2020-8492 Référence CVE CVE-2020-8617 https://www.cve.org/CVERecord?id=CVE-2020-8617 Référence CVE CVE-2020-8622 https://www.cve.org/CVERecord?id=CVE-2020-8622 Référence CVE CVE-2020-8624 https://www.cve.org/CVERecord?id=CVE-2020-8624 Référence CVE CVE-2020-8625 https://www.cve.org/CVERecord?id=CVE-2020-8625 Référence CVE CVE-2020-8927 https://www.cve.org/CVERecord?id=CVE-2020-8927 Référence CVE CVE-2020-9948 https://www.cve.org/CVERecord?id=CVE-2020-9948 Référence CVE CVE-2020-9951 https://www.cve.org/CVERecord?id=CVE-2020-9951 Référence CVE CVE-2020-9983 https://www.cve.org/CVERecord?id=CVE-2020-9983 Référence CVE CVE-2021-1817 https://www.cve.org/CVERecord?id=CVE-2021-1817 Référence CVE CVE-2021-1820 https://www.cve.org/CVERecord?id=CVE-2021-1820 Référence CVE CVE-2021-1825 https://www.cve.org/CVERecord?id=CVE-2021-1825 Référence CVE CVE-2021-1826 https://www.cve.org/CVERecord?id=CVE-2021-1826 Référence CVE CVE-2021-20271 https://www.cve.org/CVERecord?id=CVE-2021-20271 Référence CVE CVE-2021-20305 https://www.cve.org/CVERecord?id=CVE-2021-20305 Référence CVE CVE-2021-20578 https://www.cve.org/CVERecord?id=CVE-2021-20578 Référence CVE CVE-2021-2163 https://www.cve.org/CVERecord?id=CVE-2021-2163 Référence CVE CVE-2021-22543 https://www.cve.org/CVERecord?id=CVE-2021-

Official advisory
CERT-FR · French · CERTFR-2021-AVI-314Multiples vulnérabilités dans les produits Apple

.cve.org/CVERecord?id=CVE-2021-1807 Référence CVE CVE-2021-1808 https://www.cve.org/CVERecord?id=CVE-2021-1808 Référence CVE CVE-2021-1809 https://www.cve.org/CVERecord?id=CVE-2021-1809 Référence CVE CVE-2021-1810 https://www.cve.org/CVERecord?id=CVE-2021-1810 Référence CVE CVE-2021-1811 https://www.cve.org/CVERecord?id=CVE-2021-1811 Référence CVE CVE-2021-1813 https://www.cve.org/CVERecord?id=CVE-2021-1813 Référence CVE CVE-2021-1814 https://www.cve.org/CVERecord?id=CVE-2021-1814 Référence CVE CVE-2021-1815 https://www.cve.org/CVERecord?id=CVE-2021-1815 Référence CVE CVE-2021-1816 https://www.cve.org/CVERecord?id=CVE-2021-1816 Référence CVE CVE-2021-1817 https://www.cve.org/CVERecord?id=CVE-2021-1817 Référence CVE CVE-2021-1820 https://www.cve.org/CVERecord?id=CVE-2021-1820 Référence CVE CVE-2021-1822 https://www.cve.org/CVERecord?id=CVE-2021-1822 Référence CVE CVE-2021-1824 https://www.cve.org/CVERecord?id=CVE-2021-1824 Référence CVE CVE-2021-1825 https://www.cve.org/CVERecord?id=CVE-2021-1825 Référence CVE CVE-2021-1826 https://www.cve.org/CVERecord?id=CVE-2021-1826 Référence CVE CVE-2021-1828 https://www.cve.org/CVERecord?id=CVE-2021-1828 Référence CVE CVE-2021-1829 https://www.cve.org/CVERecord?id=CVE-2021-1829 Référence CVE CVE-2021-1830 https://www.cve.org/CVERecord?id=CVE-2021-1830 Ré

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
unspecified < 14.5; unspecified < 7.4; unspecified < 11.3
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 8 Sept 2021 · Last source change 3 Aug 2024, 16:25 UTC · CWE-787 · Out-of-bounds Write

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-2021-7281
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

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
CVE published
ENISA EUVD · EUVD-2021-7281↗CVE authority or vendor reference↗Vendor advisory↗Vendor advisory↗Vendor advisory↗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-2021-1817 · cve.blacktree.nl