CVE-2025-53521

CRITICALNVD 9.89.8—
EchelonGraph scoreHIGH confidence

Score elevated to 9.8 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2026-03-27), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 9.8 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, ghsa, nvd
Trending — 4 sources updated this weekExploited in the wild
9.8EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS PROB: 2%CVSS: 9.8Exploit: cisa kev · ssvc activeExposed: 0

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

When a BIG-IP APM access policy is configured on a virtual server, specific malicious traffic can lead to Remote Code Execution (RCE).  

Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

CVSS v3
9.8
EG Score
9.8(high)
EG Risk
99(Act)
EG Risk 99/100SSVC: Act

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
Severity98% × 45%
Exploitation100% × 40%
Automatability100% × 15%
Action: Fix now — active exploitation, automatable, high impact.
EPSS PROB
2%
EPSS %ILE
81%
KEV
⚠ Exploited

Published

October 15, 2025

Last Modified

April 2, 2026

Advisory Details (2)

Auto-updated Jul 27, 2026
⚠️ Active exploitation confirmed. Patch available. Sources: cisa.
cisa Patch Available🔴 Active Exploitation

Known Exploited Vulnerabilities Catalog | CISA

Known Exploited Vulnerabilities Catalog | CISA. Listed in CISA Known Exploited Vulnerabilities catalog.

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-53521
generic

myF5

https://my.f5.com/manage/s/article/K000156741

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 39× in last 7d / 213× 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.

Showing the most recent 100 of 473 total refreshes for this CVE.

  1. 2026-07-29 00:12 UTCGHSA enrichment
  2. 2026-07-28 19:48 UTCEG score recompute
  3. 2026-07-28 19:48 UTCGHSA enrichment
  4. 2026-07-28 15:35 UTCEPSS rescore
  5. 2026-07-28 15:23 UTCGHSA enrichment
  6. 2026-07-28 10:59 UTCGHSA enrichment
  7. 2026-07-28 06:34 UTCGHSA enrichment
  8. 2026-07-28 02:08 UTCGHSA enrichment
  9. 2026-07-27 21:44 UTCGHSA enrichment
  10. 2026-07-27 19:24 UTCCISA KEV update
  11. 2026-07-27 17:20 UTCEG score recompute
  12. 2026-07-27 17:20 UTCGHSA enrichment
  13. 2026-07-27 17:17 UTCCISA KEV update
  14. 2026-07-27 12:56 UTCGHSA enrichment
  15. 2026-07-27 08:31 UTCGHSA enrichment
  16. 2026-07-27 04:07 UTCGHSA enrichment
  17. 2026-07-26 23:43 UTCGHSA enrichment
  18. 2026-07-26 19:19 UTCGHSA enrichment
  19. 2026-07-26 14:55 UTCEG score recompute
  20. 2026-07-26 14:55 UTCGHSA enrichment
  21. 2026-07-26 14:54 UTCEPSS rescore
  22. 2026-07-26 10:31 UTCEG score recompute
  23. 2026-07-26 10:31 UTCGHSA enrichment
  24. 2026-07-26 06:06 UTCGHSA enrichment
  25. 2026-07-26 01:41 UTCEG score recompute
Show 75 more
  1. 2026-07-26 01:41 UTCGHSA enrichment
  2. 2026-07-25 14:17 UTCEPSS rescore
  3. 2026-07-24 14:17 UTCEPSS rescore
  4. 2026-07-23 14:18 UTCEPSS rescore
  5. 2026-07-23 02:58 UTCEG score recompute
  6. 2026-07-22 21:37 UTCEG score recompute
  7. 2026-07-22 21:36 UTCGHSA enrichment
  8. 2026-07-22 19:40 UTCCISA KEV update
  9. 2026-07-22 16:55 UTCEG score recompute
  10. 2026-07-22 16:55 UTCGHSA enrichment
  11. 2026-07-22 14:08 UTCEPSS rescore
  12. 2026-07-22 14:07 UTCEPSS rescore
  13. 2026-07-22 12:31 UTCGHSA enrichment
  14. 2026-07-22 08:07 UTCGHSA enrichment
  15. 2026-07-22 03:43 UTCGHSA enrichment
  16. 2026-07-21 23:18 UTCGHSA enrichment
  17. 2026-07-21 17:52 UTCEG score recompute
  18. 2026-07-21 17:52 UTCGHSA enrichment
  19. 2026-07-21 15:24 UTCEPSS rescore
  20. 2026-07-21 14:37 UTCCISA KEV update
  21. 2026-07-21 13:27 UTCGHSA enrichment
  22. 2026-07-21 09:02 UTCGHSA enrichment
  23. 2026-07-21 04:38 UTCGHSA enrichment
  24. 2026-07-21 00:14 UTCGHSA enrichment
  25. 2026-07-20 19:49 UTCEG score recompute
  26. 2026-07-20 19:49 UTCGHSA enrichment
  27. 2026-07-20 17:08 UTCEPSS rescore
  28. 2026-07-20 15:24 UTCGHSA enrichment
  29. 2026-07-20 10:58 UTCGHSA enrichment
  30. 2026-07-20 06:34 UTCGHSA enrichment
  31. 2026-07-20 02:03 UTCGHSA enrichment
  32. 2026-07-19 21:39 UTCGHSA enrichment
  33. 2026-07-19 17:15 UTCEG score recompute
  34. 2026-07-19 17:15 UTCGHSA enrichment
  35. 2026-07-19 14:30 UTCEPSS rescore
  36. 2026-07-19 14:30 UTCEPSS rescore
  37. 2026-07-19 12:51 UTCGHSA enrichment
  38. 2026-07-19 08:28 UTCGHSA enrichment
  39. 2026-07-19 04:03 UTCEG score recompute
  40. 2026-07-19 04:03 UTCGHSA enrichment
  41. 2026-07-19 02:28 UTCEPSS rescore
  42. 2026-07-18 23:39 UTCGHSA enrichment
  43. 2026-07-18 19:15 UTCGHSA enrichment
  44. 2026-07-18 14:51 UTCGHSA enrichment
  45. 2026-07-18 10:27 UTCEG score recompute
  46. 2026-07-18 10:27 UTCGHSA enrichment
  47. 2026-07-18 10:04 UTCEPSS rescore
  48. 2026-07-18 06:03 UTCGHSA enrichment
  49. 2026-07-18 01:38 UTCGHSA enrichment
  50. 2026-07-17 21:14 UTCGHSA enrichment
  51. 2026-07-17 16:50 UTCGHSA enrichment
  52. 2026-07-17 12:25 UTCGHSA enrichment
  53. 2026-07-17 08:00 UTCEG score recompute
  54. 2026-07-17 08:00 UTCGHSA enrichment
  55. 2026-07-17 03:36 UTCGHSA enrichment
  56. 2026-07-16 23:12 UTCGHSA enrichment
  57. 2026-07-16 18:48 UTCGHSA enrichment
  58. 2026-07-16 17:04 UTCCISA KEV update
  59. 2026-07-16 17:02 UTCEPSS rescore
  60. 2026-07-16 14:23 UTCGHSA enrichment
  61. 2026-07-16 09:58 UTCGHSA enrichment
  62. 2026-07-16 05:34 UTCGHSA enrichment
  63. 2026-07-16 01:10 UTCGHSA enrichment
  64. 2026-07-15 20:45 UTCGHSA enrichment
  65. 2026-07-15 16:57 UTCEPSS rescore
  66. 2026-07-15 16:57 UTCEPSS rescore
  67. 2026-07-15 16:49 UTCCISA KEV update
  68. 2026-07-15 16:20 UTCGHSA enrichment
  69. 2026-07-15 15:04 UTCCISA KEV update
  70. 2026-07-15 11:56 UTCGHSA enrichment
  71. 2026-07-15 07:32 UTCGHSA enrichment
  72. 2026-07-15 03:08 UTCGHSA enrichment
  73. 2026-07-15 01:59 UTCEPSS rescore
  74. 2026-07-15 01:59 UTCEPSS rescore
  75. 2026-07-14 22:44 UTCGHSA enrichment

Frequently asked(6)

What is CVE-2025-53521?
CVE-2025-53521 is a critical vulnerability published on October 15, 2025. When a BIG-IP APM access policy is configured on a virtual server, specific malicious traffic can lead to Remote Code Execution (RCE). Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
When was CVE-2025-53521 disclosed?
CVE-2025-53521 was first published in the National Vulnerability Database on October 15, 2025, with the most recent update on April 2, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-53521 actively exploited?
Yes. CISA added CVE-2025-53521 to the Known Exploited Vulnerabilities catalog on March 27, 2026, affecting F5 BIG-IP. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2025-53521?
CVE-2025-53521 has a CVSS v3 base score of 9.8 (NVD).
Which products are affected by CVE-2025-53521?
CVE-2025-53521 affects F5 BIG-IP. The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.
How do I remediate CVE-2025-53521?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-53521, 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.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2025-53521

Explore →

Is Your Infrastructure Affected by CVE-2025-53521?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs