CVE-2026-16821

HIGHNVD 7.87.8—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.8 under NVD CVSS v3. EPSS exploit probability: 0.1%, top 99% of all CVEs by exploit prediction. GitHub Security Advisory enrichment pending alignment with NVD CVSS.

Triggered by: NVD CVSS baseline
Sources: epss, ghsa, nvd
Trending — 3 sources updated this week
7.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.8Exploit: None knownExposed: 0

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

IBM AIX 7.2, and 7.3 and IBM PowerVM VIOS 4.1 could allow a local attacker to gain elevated privileges due to a format string vulnerability.

CVSS v3
7.8
EG Score
7.8(medium)
EG Risk
35(Track)
EG Risk 35/100SSVC: 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
Severity78% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
1%
KEV
Not listed

Published

August 28, 2026

Last Modified

September 2, 2026

Advisory Details (1)

Auto-updated Aug 28, 2026
No patch confirmed yet.
generic

Security Bulletin: Vulnerabilities in IBM AIX and PowerVM VIOS

https://www.ibm.com/support/pages/node/7283858

Vendor Advisories for CVE-2026-16821(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 26× in last 7d / 92× 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. 2026-09-19 16:50 UTCEG score recompute
  2. 2026-09-19 16:50 UTCGHSA enrichment
  3. 2026-09-19 05:50 UTCEG score recompute
  4. 2026-09-19 05:50 UTCGHSA enrichment
  5. 2026-09-18 19:27 UTCEPSS rescore
  6. 2026-09-18 18:48 UTCGHSA enrichment
  7. 2026-09-18 07:49 UTCGHSA enrichment
  8. 2026-09-17 20:50 UTCEG score recompute
  9. 2026-09-17 20:50 UTCGHSA enrichment
  10. 2026-09-17 08:43 UTCGHSA enrichment
  11. 2026-09-16 21:44 UTCEG score recompute
  12. 2026-09-16 21:44 UTCGHSA enrichment
  13. 2026-09-16 14:07 UTCEPSS rescore
  14. 2026-09-16 10:45 UTCEG score recompute
  15. 2026-09-16 10:45 UTCGHSA enrichment
  16. 2026-09-16 05:14 UTCEPSS rescore
  17. 2026-09-15 23:40 UTCGHSA enrichment
  18. 2026-09-15 12:41 UTCEG score recompute
  19. 2026-09-15 12:41 UTCGHSA enrichment
  20. 2026-09-15 01:42 UTCGHSA enrichment
  21. 2026-09-14 14:43 UTCGHSA enrichment
  22. 2026-09-14 03:44 UTCGHSA enrichment
  23. 2026-09-13 16:45 UTCGHSA enrichment
  24. 2026-09-13 05:46 UTCGHSA enrichment
  25. 2026-09-12 18:47 UTCEG score recompute
Show 67 more
  1. 2026-09-12 18:47 UTCGHSA enrichment
  2. 2026-09-12 15:00 UTCEPSS rescore
  3. 2026-09-12 07:47 UTCGHSA enrichment
  4. 2026-09-11 20:48 UTCEG score recompute
  5. 2026-09-11 20:48 UTCGHSA enrichment
  6. 2026-09-11 14:52 UTCEPSS rescore
  7. 2026-09-11 09:44 UTCEG score recompute
  8. 2026-09-11 09:43 UTCGHSA enrichment
  9. 2026-09-11 09:36 UTCEPSS rescore
  10. 2026-09-10 22:44 UTCGHSA enrichment
  11. 2026-09-10 11:45 UTCEG score recompute
  12. 2026-09-10 11:45 UTCGHSA enrichment
  13. 2026-09-10 09:34 UTCEPSS rescore
  14. 2026-09-09 23:52 UTCGHSA enrichment
  15. 2026-09-09 11:25 UTCGHSA enrichment
  16. 2026-09-09 00:26 UTCEG score recompute
  17. 2026-09-09 00:26 UTCGHSA enrichment
  18. 2026-09-08 22:00 UTCEPSS rescore
  19. 2026-09-08 13:15 UTCGHSA enrichment
  20. 2026-09-08 02:14 UTCEG score recompute
  21. 2026-09-08 02:13 UTCGHSA enrichment
  22. 2026-09-07 16:01 UTCEPSS rescore
  23. 2026-09-07 15:15 UTCGHSA enrichment
  24. 2026-09-07 04:15 UTCGHSA enrichment
  25. 2026-09-06 17:12 UTCEG score recompute
  26. 2026-09-06 17:12 UTCGHSA enrichment
  27. 2026-09-06 13:47 UTCEPSS rescore
  28. 2026-09-06 06:12 UTCGHSA enrichment
  29. 2026-09-05 19:09 UTCEG score recompute
  30. 2026-09-05 19:09 UTCGHSA enrichment
  31. 2026-09-05 08:11 UTCGHSA enrichment
  32. 2026-09-04 21:11 UTCEG score recompute
  33. 2026-09-04 21:11 UTCGHSA enrichment
  34. 2026-09-04 10:12 UTCEG score recompute
  35. 2026-09-04 10:12 UTCGHSA enrichment
  36. 2026-09-04 05:06 UTCEPSS rescore
  37. 2026-09-03 23:12 UTCGHSA enrichment
  38. 2026-09-03 12:11 UTCGHSA enrichment
  39. 2026-09-03 01:10 UTCEG score recompute▲ 0.80
  40. 2026-09-03 01:10 UTCGHSA enrichment
  41. 2026-09-02 14:22 UTCNVD updateCVSS v3 → 7.8
  42. 2026-09-02 14:11 UTCEPSS rescore
  43. 2026-09-02 14:08 UTCGHSA enrichment
  44. 2026-09-02 03:06 UTCGHSA enrichment
  45. 2026-09-01 16:07 UTCEG score recompute
  46. 2026-09-01 16:07 UTCGHSA enrichment
  47. 2026-09-01 13:53 UTCEPSS rescore
  48. 2026-09-01 04:39 UTCEG score recompute
  49. 2026-09-01 04:39 UTCGHSA enrichment
  50. 2026-09-01 04:04 UTCEG score recompute
  51. 2026-09-01 04:04 UTCGHSA enrichment
  52. 2026-08-31 19:30 UTCGHSA enrichment
  53. 2026-08-31 14:27 UTCEG score recompute
  54. 2026-08-31 14:26 UTCGHSA enrichment
  55. 2026-08-31 14:01 UTCEG score recompute
  56. 2026-08-31 14:01 UTCGHSA enrichment
  57. 2026-08-31 05:36 UTCGHSA enrichment
  58. 2026-08-30 18:38 UTCGHSA enrichment
  59. 2026-08-30 07:39 UTCEG score recompute
  60. 2026-08-30 07:39 UTCGHSA enrichment
  61. 2026-08-30 01:22 UTCEPSS rescore
  62. 2026-08-29 20:40 UTCGHSA enrichment
  63. 2026-08-29 09:40 UTCEG score recompute
  64. 2026-08-29 09:40 UTCGHSA enrichment
  65. 2026-08-28 22:41 UTCEG score recompute
  66. 2026-08-28 22:01 UTCEG score recompute
  67. 2026-08-28 21:59 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-16821?
CVE-2026-16821 is a high vulnerability published on August 28, 2026. IBM AIX 7.2, and 7.3 and IBM PowerVM VIOS 4.1 could allow a local attacker to gain elevated privileges due to a format string vulnerability.
When was CVE-2026-16821 disclosed?
CVE-2026-16821 was first published in the National Vulnerability Database on August 28, 2026, with the most recent update on September 2, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-16821 actively exploited?
CVE-2026-16821 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 99.2% of all scored CVEs.
What is the CVSS score of CVE-2026-16821?
CVE-2026-16821 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2026-16821?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-16821, 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

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