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Fencer Intel
high 8.8

CVE-2021-41282 in the critical feed json

diag_routes.php in pfSense 2.5.2 allows sed data injection.

published 4y ago modified 4mo ago also EUVD-2021-28312

cvss
8.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
87.1%
EPSS 87.1% chance of exploitation in 30 days, percentile 99.7%
public exploits
1
Metasploit, plus a Nuclei check

Summary

diag_routes.php in pfSense 2.5.2 allows sed data injection. Authenticated users are intended to be able to view data about the routes set in the firewall. The data is retrieved by executing the netstat utility, and then its output is parsed via the sed utility. Although the common protection mechanisms against command injection (i.e., the usage of the escapeshellarg function for the arguments) are used, it is still possible to inject sed-specific code and write an arbitrary file in an arbitrary location.

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Timeline

  1. First public exploit (Metasploit exploit/unix/http/pfsense_diag_routes_webshell)
  2. Published

Exploit prediction

87.11% chance of exploitation in the next 30 days, higher than 99.7% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

CVSS scores

assigned by version score vector
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 9.0 AV:N/AC:L/Au:S/C:C/I:C/A:C

Classification

Weakness
  • CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component

References

Sources

Fencer Intel 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.