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Full vulnerability report · 2017
CVE-2017-8521High confidence

Microsoft Corporation Microsoft Edge: Improper Restriction of Operations within the Bounds of a Memory Buffer

Microsoft Corporation · Microsoft Edge

7.5HighCVSS 3.0
Recommended action
Within 7 days

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

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:High, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • EPSS is 6.23% 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.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Microsoft Corporation Microsoft Edge 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 30 daysRemediation target: Within 180 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.

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-2017-17471

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.

Patch available
01

What, why and how

Microsoft Edge in Windows 10 1703 allows an attacker to execute arbitrary code in the context of the current user when the Edge JavaScript scripting engine fails to handle objects in memory, aka "Scripting Engine Memory Corruption Vulnerability". This CVE ID is unique from CVE-2017-8499, CVE-2017-8520, CVE-2017-8548, and CVE-2017-8549.

What

Microsoft Edge in Windows 10 1703 allows an attacker to execute arbitrary code in the context of the current user when the Edge JavaScript scripting engine fails to handle objects in memory, aka "Scripting Engine Memory Corruption Vulnerability". This CVE ID is unique from CVE-2017-8499, CVE-2017-8520, CVE-2017-8548, and CVE-2017-8549.

Why

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program 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

Microsoft Edge in Windows 10 1703 allows an attacker to execute arbitrary code in the context of the current user when the Edge JavaScript scripting engine fails to handle objects in memory, aka "Scripting Engine Memory Corruption Vulnerability". This CVE ID is unique from CVE-2017-8499, CVE-2017-8520, CVE-2017-8548, and CVE-2017-8549.

Why

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program 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 → Improper Restriction of Operations within the Bounds of a Memory Buffer → 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
High: exploitation depends on specific conditions
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-119 ↗

CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer. The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Common Vulnerability Scoring System 3.0: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.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-119
A

Official authority intelligence

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

CERT-FR · French · CERTFR-2017-AVI-179Multiples vulnérabilités dans Microsoft Edge

De multiples vulnérabilités ont été corrigées dans Microsoft Edge . Elles permettent à un attaquant de provoquer une exécution de code arbitraire à distance, un contournement de la politique de sécurité et une atteinte à la confidentialité des données.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2017-004358Microsoft Windows 10 および Windows Server 2016 の Microsoft Edge における情報を取得される脆弱性

Microsoft Windows 10 Gold、1511、1607、1703、および Windows Server 2016 の Microsoft Edge には、メモリ内のオブジェクトを適切に処理しない場合、情報を取得され、ユーザのシステムを侵害される脆弱性が存在します。 ベンダは、本脆弱性を「スクリプト エンジンのメモリ破損の脆弱性」として公開しています。 本脆弱性は、CVE-2017-8499、CVE-2017-8520、CVE-2017-8521、および CVE-2017-8549 とは異なる脆弱性です。

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2017-004334Microsoft Windows 10 および Windows Server 2016 の Microsoft Edge における情報を取得される脆弱性

Microsoft Windows 10 Gold、1511、1607、1703、および Windows Server 2016 の Microsoft Edge には、メモリ内のオブジェクトを適切に処理しない場合、情報を取得され、ユーザのシステムを侵害される脆弱性が存在します。 ベンダは、本脆弱性を「スクリプト エンジンのメモリ破損の脆弱性」として公開しています。 本脆弱性は、CVE-2017-8499、CVE-2017-8520、CVE-2017-8521、および CVE-2017-8548 とは異なる脆弱性です。

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2017-004331Microsoft Windows 10 の Microsoft Edge における現在のユーザのコンテキストで任意のコードを実行される脆弱性

Microsoft Windows 10 1703 の Microsoft Edge には、Edge JavaScript スクリプトエンジンがメモリ内のオブジェクトを適切に処理しない場合、現在のユーザのコンテキストで任意のコードを実行される脆弱性が存在します。 ベンダは、本脆弱性を「スクリプト エンジンのメモリ破損の脆弱性」として公開しています。 本脆弱性は、CVE-2017-8499、CVE-2017-8520、CVE-2017-8548、および CVE-2017-8549 とは異なる脆弱性です。

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2017-004330Microsoft Windows 10 の Microsoft Edge における現在のユーザのコンテキストで任意のコードを実行される脆弱性

Microsoft Windows 10 1703 の Microsoft Edge には、Edge JavaScript スクリプトエンジンがメモリ内のオブジェクトを適切に処理しない場合、現在のユーザのコンテキストで任意のコードを実行される脆弱性が存在します。 ベンダは、本脆弱性を「スクリプト エンジンのメモリ破損の脆弱性」として公開しています。 本脆弱性は、CVE-2017-8499、CVE-2017-8521、CVE-2017-8548、および CVE-2017-8549 とは異なる脆弱性です。

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2017-004328Microsoft Windows 10 の Microsoft Edge における現在のユーザのコンテキストで任意のコードを実行される脆弱性

Microsoft Windows 10 1703 の Microsoft Edge には、Edge JavaScript スクリプトエンジンがメモリ内のオブジェクトを適切に処理しない場合、現在のユーザのコンテキストで任意のコードを実行される脆弱性が存在します。 ベンダは、本脆弱性を「スクリプト エンジンのメモリ破損の脆弱性」として公開しています。 本脆弱性は、CVE-2017-8520、CVE-2017-8521、CVE-2017-8548、および CVE-2017-8549 とは異なる脆弱性です。

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: Microsoft Windows 10 1703.
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 15 Jun 2017 · Last source change 5 Aug 2024, 16:41 UTC · CWE-119 · Improper Restriction of Operations within the Bounds of a Memory Buffer

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 2026-09-01
European sourceENISA EUVD · EUVD-2017-17471
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 ↗
  1. ENISA EUVD mappingEUVD-2017-17471 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2017-17471"}
    ENISA EUVD ↗
  2. Vendor guidanceAuthoritative vendor guidance changed: added patch: portal.msrc.microsoft.com/CVE-2017-8521; added remediation: portal.msrc.microsoft.com/CVE-2017-8521.
    Before
    no authoritative guidance recorded
    After
    patch: portal.msrc.microsoft.com/CVE-2017-8521 · remediation: portal.msrc.microsoft.com/CVE-2017-8521
    portal.msrc.microsoft.com ↗
  3. Affected versionsThe structured affected or fixed version information changed.
    Before
    Microsoft Windows 10 1703. · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    Microsoft Windows 10 1703. · 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 ↗
  4. Remediation statusRemediation status changed from Awaiting fix to Patch available.
    Before
    Awaiting fix
    After
    Patch available
    portal.msrc.microsoft.com ↗
  5. SeveritySeverity changed from Unknown to High.
    Before
    Unknown
    After
    High
    NIST NVD ↗
  6. CVSS scoreCVSS score changed from not recorded to 7.5 (CVSS 3.0 · NIST NVD · CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H).
    Before
    not recorded
    After
    7.5 (CVSS 3.0 · NIST NVD · CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H)
    NIST NVD ↗
  7. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2017-17471↗Patch or update reference↗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-2017-8521 · cve.blacktree.nl