Microsoft Edge Javascript Engine ProcessLinkFailedAsmJsModule memory corruption

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
5.8	$0-$5k	0.00

Summaryinfo

A vulnerability classified as critical was found in Microsoft Edge. Affected by this vulnerability is the function InterpreterStackFrame::ProcessLinkFailedAsmJsModule of the component Javascript Engine. Executing a manipulation can lead to memory corruption. This vulnerability appears as CVE-2017-8645. The attack may be performed from remote. In addition, an exploit is available. It is advisable to implement a patch to correct this issue.

Detailsinfo

A vulnerability was found in Microsoft Edge (Web Browser) (version unknown). It has been declared as critical. This vulnerability affects the function InterpreterStackFrame::ProcessLinkFailedAsmJsModule of the component Javascript Engine. The manipulation with an unknown input leads to a memory corruption vulnerability. The CWE definition for the vulnerability is CWE-119. The product performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

Microsoft Edge in Windows 10 1511, 1607, 1703, and Windows Server 2016 allows an attacker to execute arbitrary code in the context of the current user due to the way that Microsoft browser JavaScript engines render content when handling objects in memory, aka "Scripting Engine Memory Corruption Vulnerability". This CVE ID is unique from CVE-2017-8634, CVE-2017-8635, CVE-2017-8636, CVE-2017-8638, CVE-2017-8639, CVE-2017-8640, CVE-2017-8641, CVE-2017-8646, CVE-2017-8647, CVE-2017-8655, CVE-2017-8656, CVE-2017-8657, CVE-2017-8670, CVE-2017-8671, CVE-2017-8672, and CVE-2017-8674.

The bug was discovered 08/08/2017. The weakness was presented 08/08/2017 with Google Project Zero as KB4034658 as confirmed security update guide (Website). The advisory is shared for download at portal.msrc.microsoft.com. This vulnerability was named CVE-2017-8645 since 05/03/2017. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. Technical details and also a public exploit are known. The advisory points out:

A remote code execution vulnerability exists in the way that Microsoft browser JavaScript engines render content when handling objects in memory. The vulnerability could corrupt memory in such a way that an attacker could execute arbitrary code in the context of the current user.

A public exploit has been developed by Google Security Research in Javascript and been published 2 weeks after the advisory. It is possible to download the exploit at exploit-db.com. It is declared as proof-of-concept. As 0-day the estimated underground price was around $25k-$100k. The vulnerability scanner Nessus provides a plugin with the ID 102264 (KB4034658: Windows 10 Version 1607 and Windows Server 2016 August 2017 Cumulative Update), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Windows : Microsoft Bulletins and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 91406 (Microsoft Edge Security Update for August 2017). The code used by the exploit is:

class MyClass {
    f(a) {
        print(a);
    }
 
    constructor() {
        'use asm';
        function f(v) {
            v = v | 0;
            return v | 0;
        }
        return f;
    }
 
    f2(a) {
        print(a);
    }
}
 
MyClass(1);

Applying the patch KB4034658 is able to eliminate this problem. The bugfix is ready for download at catalog.update.microsoft.com. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Exploit-DB (42469), Tenable (102264) and SecurityFocus (BID 100052†). See VDB-104989, VDB-104990, VDB-104991 and VDB-105007 for similar entries. Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

Web Browser

Vendor

Microsoft

Name

Edge

License

commercial

Website

Vendor: https://www.microsoft.com/

CPE 2.3info

🔍

CPE 2.2info

🔍

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.0
VulDB Meta Temp Score: 5.8

VulDB Base Score: 6.3
VulDB Temp Score: 5.7
VulDB Vector: 🔍
VulDB Reliability: 🔍

Vendor Base Score (Microsoft): 4.2
Vendor Vector (Microsoft): 🔍

NVD Base Score: 7.5
NVD Vector: 🔍

CVSSv2info

AV	AC	Au	C	I	A
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💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
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Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Memory corruption
CWE: CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Proof-of-Concept
Author: Google Security Research
Programming Language: 🔍
Download: 🔍

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 102264
Nessus Name: KB4034658: Windows 10 Version 1607 and Windows Server 2016 August 2017 Cumulative Update
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 802136
OpenVAS Name: Microsoft Windows Multiple Vulnerabilites (KB4034674)
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Exploit-DB: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍
Exploit Delay Time: 🔍

Patch: KB4034658

Timelineinfo

05/03/2017 🔍
08/08/2017 +97 days 🔍
08/08/2017 +0 days 🔍
08/08/2017 +0 days 🔍
08/08/2017 +0 days 🔍
08/08/2017 +0 days 🔍
08/08/2017 +0 days 🔍
08/09/2017 +1 days 🔍
08/17/2017 +8 days 🔍
08/17/2017 +0 days 🔍
12/14/2025 +3040 days 🔍

Sourcesinfo

Vendor: microsoft.com

Advisory: KB4034658
Researcher: Lokihart
Organization: Google Project Zero
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2017-8645 (🔍)
GCVE (CVE): GCVE-0-2017-8645
GCVE (VulDB): GCVE-100-105028

OVAL: 🔍

SecurityFocus: 100052 - Microsoft Edge CVE-2017-8645 Scripting Engine Remote Memory Corruption Vulnerability
SecurityTracker: 1039095

scip Labs: https://www.scip.ch/en/?labs.20161013
See also: 🔍

Entryinfo

Created: 08/09/2017 12:02
Updated: 12/14/2025 00:12
Changes: 08/09/2017 12:02 (93), 11/09/2019 11:11 (12), 01/08/2021 06:55 (2), 01/08/2021 06:59 (1), 12/14/2025 00:12 (15)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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