CVE-2020-7660Public exploitNetwork attack vector

Arbitrary JavaScript execution via placeholder collision

Published Jun 1, 2020 · Updated Aug 4, 2024

Code injection in Yahoo serialize-javascript before 3.1.0 allows remote attackers to execute arbitrary JavaScript through crafted values. The index.js placeholder-replacement pass treats a backslash-escaped placeholder inside a JSON string as a real RegExp or function marker and substitutes executable source. Exploitation requires control of two serialized values, prediction of the process-wide random placeholder UID, and later evaluation of the generated string; successful exploitation runs code in the consuming application's context.

CVSS severity8.1
High
EPSS probability2.60%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code injection in Yahoo serialize-javascript before 3.1.0 allows remote attackers to execute arbitrary JavaScript through crafted values. The index.js placeholder-replacement pass treats a backslash-escaped placeholder inside a JSON string as a real RegExp or function marker and substitutes executable source. Exploitation requires control of two serialized values, prediction of the process-wide random placeholder UID, and later evaluation of the generated string; successful exploitation runs code in the consuming application's context.

The record

CVE
CVE-2020-7660
Published
Jun 1, 2020
Updated
Aug 4, 2024
Vendor
Yahoo
Product
serialize-javascript
Classifications
CWE-502, CAPEC-586, T1059.007
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 1, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record 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=All versions prior to version 3.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Yahoo · serialize-javascriptversion=All versions prior to version 3.1.0

Published CVSS scores

8.1GitHubCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
8.1NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

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 exploitPublished

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
CAPEC-586Object Injection
T1059.007Command and Scripting Interpreter: JavaScript

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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