CVE-2020-1037Network attack vector

User-context code execution via omitted JIT bailout

Published May 21, 2020 · Updated Aug 19, 2026

Memory corruption in Microsoft Edge Legacy and ChakraCore allows remote attackers to execute code through crafted web content. The GlobOpt dead-store pass can remove a required JIT bailout for a temporary object during an implicit call, allowing a stack object to outlive its function. Exploitation requires a user to render attacker-controlled content, and successful code runs with that user's rights.

CVSS severity4.2
Medium
EPSS probability2.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in Microsoft Edge Legacy and ChakraCore allows remote attackers to execute code through crafted web content. The GlobOpt dead-store pass can remove a required JIT bailout for a temporary object during an implicit call, allowing a stack object to outlive its function. Exploitation requires a user to render attacker-controlled content, and successful code runs with that user's rights.

The record

CVE
CVE-2020-1037
Published
May 21, 2020
Updated
Aug 19, 2026
Vendor
Microsoft
Product
Microsoft Edge Legacy
Classifications
CWE-787, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 21, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 19, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.0..0 <publication

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft Edge Legacyversion=1.0..0 <publication
Microsoft · ChakraCoreversion=0 <publication

Published CVSS scores

4.2MicrosoftCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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