CVE-2021-43808Public exploitNetwork attack vector

Cross-site scripting via predictable Blade parent placeholders

Published Dec 7, 2021 · Updated Aug 4, 2024

Cross-site scripting in Laravel Framework before 6.20.42, 7.0.0 through 7.30.5, or 8.0.0 through 8.74.0 allows remote attackers to execute script. Blade's parentPlaceholder method derived parent replacement markers solely from the SHA-1 hash of predictable section names, allowing crafted values to collide with markers during rendering. Exploitation requires attacker-controlled data in an exploitable parent-template HTML structure and a user to click the malformed element; impact is browser-side script execution in that user's context.

CVSS severity6.1
Medium
EPSS probability0.80%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Laravel Framework before 6.20.42, 7.0.0 through 7.30.5, or 8.0.0 through 8.74.0 allows remote attackers to execute script. Blade's parentPlaceholder method derived parent replacement markers solely from the SHA-1 hash of predictable section names, allowing crafted values to collide with markers during rendering. Exploitation requires attacker-controlled data in an exploitable parent-template HTML structure and a user to click the malformed element; impact is browser-side script execution in that user's context.

The record

CVE
CVE-2021-43808
Published
Dec 7, 2021
Updated
Aug 4, 2024
Vendor
Laravel
Product
Laravel Framework
Classifications
CWE-327, CWE-79, T1059.007
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 7, 2021CVE 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=< 6.20.42
  2. Affected versionversion=>= 7.0.0, < 7.30.6
  3. Affected versionversion=>= 8.0.0, < 8.75.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Laravel · Laravel Frameworkversion=< 6.20.42; version=>= 7.0.0, < 7.30.6; version=>= 8.0.0, < 8.75.0

Published CVSS scores

6.1GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/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 exploitPublished

Weakness, pattern, technique

CWE-327Use of a Broken or Risky Cryptographic Algorithm
CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
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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