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Fencer Vulns
medium 5.3

CVE-2021-43808 json

Blade `@parent` Exploitation Leading To Possible XSS in Laravel

published 2021-12-07 4 y ago modified 2026-07-08 4 mo ago also GHSA-66hf-2p6w-jqfw , EUVD-2021-2455

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 57%
public exploits
0
none known

Summary

Laravel is a web application framework. Laravel prior to versions 8.75.0, 7.30.6, and 6.20.42 contain a possible cross-site scripting (XSS) vulnerability in the Blade templating engine. A broken HTML element may be clicked and the user taken to another location in their browser due to XSS. This is due to the user being able to guess the parent placeholder SHA-1 hash by trying common names of sections. If the parent template contains an exploitable HTML structure an XSS vulnerability can be exposed. This vulnerability has been patched in versions 8.75.0, 7.30.6, and 6.20.42 by determining the parent placeholder at runtime and using a random hash that is unique to each request.

Patch / fix

  • packagist laravel/framework 6.20.42, 7.30.6, 8.75.0
  • packagist illuminate/view 6.20.42, 7.30.6, 8.75.0
  • laravel framework 6.20.42, 7.30.6, 8.75.0
  • php-laravel-framework Debian 14, Debian 13, Debian 12 6.20.14+dfsg-3

debian advisories DEBIAN-CVE-2021-43808

Exploit prediction

0.83% chance of exploitation in the next 30 days, higher than 57% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/laravel/framework/security/advisories/GHSA-66hf-2p6w-jqfw referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N
NVD 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N
GitHub 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
packagist laravel/framework
<6.20.42
>=7.0.0, <7.30.6
>=8.0.0, <8.75.0
6.20.42
7.30.6
8.75.0
packagist illuminate/view
<6.20.42
>=7.0.0, <7.30.6
>=8.0.0, <8.75.0
6.20.42
7.30.6
8.75.0

Affected products

  • laravel framework

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation
  • CWE-327 Use of a Broken or Risky Cryptographic Algorithm

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.