CVE-2021-41282

HIGHNVD 8.89.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because EPSS predicts 87% probability of exploitation within the next 30 days (top 0.3% of all CVEs). NVD baseline CVSS 8.8 retained for reference. Confidence: see factors.

Triggered by: EPSS exploit prediction ≥85%
Sources: epss, ghsa, nvd
Trending — 3 sources updated this weekWeaponized
8.8
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • High exploitation likelihood — EPSS 87%
CISA-KEV: Not listedEPSS: 87%CVSS: 8.8Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
8.8
EG Score
9.0(high)
EG Risk
80(Track)
EG Risk 80/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity90% × 45%
Exploitation87% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
99.7%
KEV
Not listed

Published

March 1, 2022

Last Modified

November 21, 2024

References (8)

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 5× in last 7d / 16× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-23 02:04 UTCEG score recompute
  2. 2026-07-22 22:50 UTCEG score recompute
  3. 2026-07-22 14:06 UTCEPSS rescore
  4. 2026-07-19 02:27 UTCEPSS rescore
  5. 2026-07-17 21:29 UTCOSV refresh
  6. 2026-07-15 16:55 UTCEPSS rescore
  7. 2026-07-15 16:55 UTCEPSS rescore
  8. 2026-07-13 06:11 UTCEPSS rescore
  9. 2026-07-13 06:11 UTCEPSS rescore
  10. 2026-07-12 05:44 UTCEPSS rescore
  11. 2026-07-04 06:29 UTCEPSS rescore
  12. 2026-07-04 06:29 UTCEPSS rescore
  13. 2026-07-01 15:04 UTCEPSS rescore
  14. 2026-06-29 19:23 UTCOSV refresh
  15. 2026-06-25 13:48 UTCEPSS rescore
  16. 2026-06-25 13:48 UTCEPSS rescore
  17. 2026-06-23 21:31 UTCEPSS rescore
  18. 2026-06-23 21:31 UTCEPSS rescore
  19. 2026-06-18 17:51 UTCEPSS rescore
  20. 2026-06-18 17:51 UTCEPSS rescore
  21. 2026-06-17 17:51 UTCEPSS rescore
  22. 2026-06-17 17:51 UTCEPSS rescore
  23. 2026-06-17 17:51 UTCEPSS rescore
  24. 2026-06-15 17:46 UTCEPSS rescore
  25. 2026-06-14 23:15 UTCEPSS rescore
Show 20 more
  1. 2026-06-14 23:15 UTCEPSS rescore
  2. 2026-06-13 22:58 UTCEPSS rescore
  3. 2026-06-13 22:58 UTCEPSS rescore
  4. 2026-06-12 23:10 UTCEPSS rescore
  5. 2026-06-12 08:06 UTCOSV refresh
  6. 2026-06-10 22:16 UTCEPSS rescore
  7. 2026-06-10 22:16 UTCEPSS rescore
  8. 2026-06-10 13:20 UTCEPSS rescore
  9. 2026-06-06 13:46 UTCEPSS rescore
  10. 2026-06-06 13:46 UTCEPSS rescore
  11. 2026-06-05 22:45 UTCEPSS rescore
  12. 2026-05-28 13:43 UTCEPSS rescore
  13. 2026-05-28 13:43 UTCEPSS rescore
  14. 2026-05-26 13:42 UTCEPSS rescore
  15. 2026-05-26 13:42 UTCEPSS rescore
  16. 2026-05-26 07:17 UTCEPSS rescore
  17. 2026-05-26 07:17 UTCEPSS rescore
  18. 2026-05-26 07:17 UTCEPSS rescore
  19. 2026-05-26 02:18 UTCEG score recompute
  20. 2026-05-26 02:18 UTCGHSA enrichment

Publicly available exploits

(2 references)

Working exploit code is in the public domain (1 Metasploit module). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Metasploitexploit/unix/http/pfsense_diag_routes_webshell✓ verified
    First seen Feb 23, 2022

    pfSense Diag Routes Web Shell Upload

    Open source ↗
  • Nucleihttp/cves/2021/CVE-2021-41282.yaml
    First seen Jan 1, 2021

    pfSense - Arbitrary File Write

    Open source ↗

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2021-41282?
CVE-2021-41282 is a high vulnerability published on March 1, 2022. 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…
When was CVE-2021-41282 disclosed?
CVE-2021-41282 was first published in the National Vulnerability Database on March 1, 2022, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-41282 actively exploited?
CVE-2021-41282 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 99.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-41282?
CVE-2021-41282 has a CVSS v3 base score of 8.8 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
How do I remediate CVE-2021-41282?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-41282, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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