CVE-2021-41282

CRITICALNVD 8.89.0
EchelonGraph scoreHIGH confidence

“▲” beside the score: it is higher than NVD's CVSS score.

Score elevated to 9.0 because EPSS predicted 87% probability of exploitation within the next 30 days (99th percentile of EPSS-scored CVEs) when EchelonGraph scored this CVE. NVD baseline CVSS 8.8 retained for reference. Confidence: see factors.

Triggered by: EPSS exploit prediction (continuous uplift above 30%)
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Trending — 3 sources updated this weekWeaponized
9.0EG
EchelonGraph verdictPlan mitigationRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High exploitation likelihood — EPSS 87%
  • Public exploit code is available (Metasploit)
CISA-KEV: Not listedEPSS PROB: 87%CVSS: 8.8Exploit: MetasploitExposed services: Not assessed

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

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
9.0CRITICALhigh confidence
EG Risk
74
EG Risk 74/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity88% × 45%
Impact severity (EG Severity): CVSS 8.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation87% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's BOD 26-04 default: no one has published Automatable for this CVE, and CISA treats it as “no” for a CVE not in KEV.
SSVC (CISA's decision table, applied by EchelonGraph): Track at low, Track* at medium and Attend at high mission impact.
Exploitation public PoC (exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: No fix is confirmed yet. Restrict network exposure of the affected system within your standard update timelines at low or medium mission impact and sooner than that at high, and watch for a fix.
EPSS PROB
87%
EPSS %ILE
99th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (9.0): severity, escalated by confirmed exploitation. This CVE's 9.0 is EPSS's lift toward 9.0 from its impact severity (EG Severity, CVSS 8.8 HIGH): a likelihood of exploitation, not impact.

EG Severity
8.8 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
87% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-22). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track* at medium mission impactTrack at low, Track* at medium and Attend at high mission impact.CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low, Track* at medium and Attend at high mission impact.

No fix is confirmed yet. Restrict network exposure of the affected system within your standard update timelines at low or medium mission impact and sooner than that at high, and watch for a fix.

Exploitation public PoC (exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

March 1, 2022

Last Modified

November 21, 2024

Advisory Details (4)

Auto-updated Aug 31, 2026
No fix on record yet.
Web page

Shielder - Remote Code Execution in pfSense <= 2.5.2

https://www.shielder.it/advisories/pfsense-remote-command-execution/
Web pageMentions a patch (unverified)

Shielder - Advisories

https://www.shielder.it/advisories/
Web pageMentions a patch (unverified)

22.01/2.6.0 New Features and Changes | pfSense Documentation

https://docs.netgate.com/pfsense/en/latest/releases/22-01_2-6-0.html

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 14× in last 7d / 30× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 84 of 92 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 16 repeat rows among the latest 100 are merged into the row they repeat. The 8 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-23 00:05 UTCEG score recompute
  2. 2026-10-23 00:04 UTCGHSA enrichmentGHSA-px3p-5c29-4jxr · GitHub severity HIGH · GitHub CVSS 8.8
  3. 2026-10-21 21:46 UTCEG score recompute
  4. 2026-10-21 21:45 UTCGHSA enrichmentGHSA-px3p-5c29-4jxr · GitHub severity HIGH · GitHub CVSS 8.8
  5. 2026-10-21 16:28 UTCEPSS rescoreEPSS 87% · 99th percentile
  6. 2026-10-20 19:27 UTCEG score recompute
  7. 2026-10-20 19:27 UTCGHSA enrichmentGHSA-px3p-5c29-4jxr · GitHub severity HIGH · GitHub CVSS 8.8
  8. 2026-10-19 17:10 UTCEG score recompute
  9. 2026-10-19 17:10 UTCGHSA enrichmentGHSA-px3p-5c29-4jxr · GitHub severity HIGH · GitHub CVSS 8.8
  10. 2026-10-19 16:28 UTCEPSS rescoreEPSS 87% · 99th percentile
  11. 2026-10-18 14:53 UTCGHSA enrichmentGHSA-px3p-5c29-4jxr · GitHub severity HIGH · GitHub CVSS 8.8
  12. 2026-10-18 08:54 UTCEG score recompute
  13. 2026-10-17 12:37 UTCEG score recompute
  14. 2026-10-17 12:37 UTCGHSA enrichmentGHSA-px3p-5c29-4jxr · GitHub severity HIGH · GitHub CVSS 8.8
  15. 2026-10-16 10:21 UTCEG score recompute
  16. 2026-10-16 10:21 UTCGHSA enrichmentGHSA-px3p-5c29-4jxr · GitHub severity HIGH · GitHub CVSS 8.8
  17. 2026-10-15 08:04 UTCEG score recompute
  18. 2026-10-15 08:04 UTCGHSA enrichmentGHSA-px3p-5c29-4jxr · GitHub severity HIGH · GitHub CVSS 8.8
  19. 2026-10-14 16:29 UTCEPSS rescoreEPSS 87% · 99th percentile
  20. 2026-10-14 04:04 UTCEG score recompute
  21. 2026-10-14 04:03 UTCGHSA enrichmentGHSA-px3p-5c29-4jxr · GitHub severity HIGH · GitHub CVSS 8.8
  22. 2026-10-12 23:54 UTCGHSA enrichmentGHSA-px3p-5c29-4jxr · GitHub severity HIGH · GitHub CVSS 8.8
  23. 2026-10-12 19:09 UTCEG score recompute
  24. 2026-10-11 23:35 UTCEG score recompute
  25. 2026-10-08 16:40 UTCEPSS rescoreEPSS 87% · 99th percentile
Show 59 more
  1. 2026-10-05 17:40 UTCEPSS rescoreEPSS 87% · 99th percentile
  2. 2026-09-30 15:41 UTCEG score recompute
  3. 2026-09-30 15:00 UTCEPSS rescoreEPSS 87% · 99th percentile
  4. 2026-09-25 03:54 UTCOSV refresh
  5. 2026-09-24 14:00 UTCEPSS rescoreEPSS 87% · 99th percentile
  6. 2026-09-23 13:44 UTCEPSS rescoreEPSS 87% · 99th percentile
  7. 2026-09-22 14:44 UTCEPSS rescoreEPSS 87% · 99th percentile
  8. 2026-09-21 20:28 UTCEPSS rescoreEPSS 87% · 99th percentile
  9. 2026-09-18 19:23 UTCEPSS rescoreEPSS 87% · 99th percentile
  10. 2026-09-17 19:23 UTCEPSS rescoreEPSS 87% · 99th percentile
  11. 2026-09-15 03:06 UTCEPSS rescoreEPSS 87% · 99th percentile
  12. 2026-09-06 13:45 UTCEPSS rescoreEPSS 87% · 99th percentile
  13. 2026-09-05 19:51 UTCOSV refresh
  14. 2026-09-05 15:25 UTCEPSS rescoreEPSS 87% · 99th percentile
  15. 2026-09-04 13:57 UTCEPSS rescoreEPSS 87% · 99th percentile
  16. 2026-09-04 05:03 UTCEPSS rescoreEPSS 87% · 99th percentile
  17. 2026-08-30 19:14 UTCEPSS rescoreEPSS 87% · 99th percentile
  18. 2026-08-30 01:19 UTCEPSS rescoreEPSS 87% · 99th percentile
  19. 2026-08-28 21:37 UTCEPSS rescoreEPSS 87% · 99th percentile
  20. 2026-08-27 14:22 UTCEPSS rescoreEPSS 87% · 99th percentile
  21. 2026-08-26 14:43 UTCEPSS rescoreEPSS 87% · 99th percentile
  22. 2026-08-24 14:13 UTCEPSS rescoreEPSS 87% · 99th percentile
  23. 2026-08-23 00:16 UTCEPSS rescoreEPSS 87% · 99th percentile
  24. 2026-08-20 22:52 UTCEPSS rescoreEPSS 87% · 99th percentile
  25. 2026-08-19 06:32 UTCOSV refresh
  26. 2026-08-17 13:44 UTCEPSS rescoreEPSS 87% · 99th percentile
  27. 2026-08-16 14:53 UTCEPSS rescoreEPSS 87% · 99th percentile
  28. 2026-08-15 01:27 UTCEPSS rescoreEPSS 87% · 99th percentile
  29. 2026-08-12 13:48 UTCEPSS rescoreEPSS 87% · 99th percentile
  30. 2026-08-04 10:34 UTCEPSS rescoreEPSS 87% · 99th percentile
  31. 2026-08-04 02:27 UTCOSV refresh
  32. 2026-08-01 04:13 UTCEPSS rescoreEPSS 87% · 99th percentile
  33. 2026-07-25 14:15 UTCEPSS rescoreEPSS 87% · 99th percentile
  34. 2026-07-24 14:15 UTCEPSS rescoreEPSS 87% · 99th percentile
  35. 2026-07-23 02:04 UTCEG score recompute
  36. 2026-07-22 22:50 UTCEG score recompute
  37. 2026-07-22 14:06 UTCEPSS rescoreEPSS 87% · 99th percentile
  38. 2026-07-19 02:27 UTCEPSS rescoreEPSS 87% · 99th percentile
  39. 2026-07-17 21:29 UTCOSV refresh
  40. 2026-07-15 16:55 UTCEPSS rescoreEPSS 87% · 99th percentile
  41. 2026-07-13 06:11 UTCEPSS rescoreEPSS 87% · 99th percentile
  42. 2026-07-12 05:44 UTCEPSS rescoreEPSS 87% · 99th percentile
  43. 2026-07-04 06:29 UTCEPSS rescoreEPSS 87% · 99th percentile
  44. 2026-07-01 15:04 UTCEPSS rescoreEPSS 87% · 99th percentile
  45. 2026-06-29 19:23 UTCOSV refresh
  46. 2026-06-25 13:48 UTCEPSS rescoreEPSS 87% · 99th percentile
  47. 2026-06-23 21:31 UTCEPSS rescoreEPSS 87% · 99th percentile
  48. 2026-06-18 17:51 UTCEPSS rescoreEPSS 87% · 99th percentile
  49. 2026-06-17 17:51 UTCEPSS rescoreEPSS 87% · 99th percentile
  50. 2026-06-15 17:46 UTCEPSS rescoreEPSS 87% · 99th percentile
  51. 2026-06-14 23:15 UTCEPSS rescoreEPSS 91% · 99th percentile
  52. 2026-06-13 22:58 UTCEPSS rescoreEPSS 91% · 99th percentile
  53. 2026-06-12 23:10 UTCEPSS rescoreEPSS 91% · 99th percentile
  54. 2026-06-12 08:06 UTCOSV refresh
  55. 2026-06-10 22:16 UTCEPSS rescoreEPSS 91% · 99th percentile
  56. 2026-06-10 13:20 UTCEPSS rescoreEPSS 91% · 99th percentile
  57. 2026-06-06 13:46 UTCEPSS rescoreEPSS 91% · 99th percentile
  58. 2026-06-05 22:45 UTCEPSS rescoreEPSS 91% · 99th percentile
  59. 2026-05-28 13:43 UTCEPSS rescoreEPSS 91% · 99th percentile

Publicly available exploits

(2 references)

Public exploit code is referenced for this CVE (1 Metasploit module), as is 1 Nuclei detection template. A detection template checks whether a system is affected; it is not necessarily exploit code. No fix is confirmed yet, so defenders should restrict or isolate affected systems accordingly until one is published.

  • Metasploitexploit/unix/http/pfsense_diag_routes_webshell✓ verified
    Published Mar 3, 2022

    pfSense Diag Routes Web Shell Upload

    Open source ↗
  • Nucleihttp/cves/2021/CVE-2021-41282.yaml
    Published Mar 19, 2022

    pfSense - Arbitrary File Write

    Open source ↗

Frequently asked(5)

What is CVE-2021-41282?
CVE-2021-41282 is a critical-severity vulnerability; its CVE record was 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 the CVE record for CVE-2021-41282 published?
The CVE record for CVE-2021-41282 was published on March 1, 2022. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of November 21, 2024; the record at its source may have been updated since.
Is CVE-2021-41282 actively exploited?
CVE-2021-41282 is not currently on CISA's Known Exploited Vulnerabilities catalog. EchelonGraph's EG-KEV model places it in Tier 2 (Weaponized), which is not evidence of exploitation: a Metasploit module exists for it. EchelonGraph does not test whether exploit code works. FIRST EPSS estimates a 87% probability of exploitation in the next 30 days (99th percentile of EPSS-scored CVEs).
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 (CRITICAL).
How do I remediate CVE-2021-41282?
No fix for CVE-2021-41282 is confirmed yet. Until one is published, restrict network exposure of the affected system — for example, keep it off the internet or limit it to trusted networks — and watch for a fix.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2021-41282

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