CVE-2026-21788

MEDIUMPre-NVD 5.45.4—
EchelonGraph scoreMEDIUM confidence

Score 5.4 from GitHub Security Advisory published 2026-03-19. a secondary CVSS source baseline 5.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
5.4EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.4Exploit: None knownExposed: 0

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

HCL Connections is vulnerable to a cross-site scripting attack where an attacker may leverage this issue to execute arbitrary script code in the browser of an unsuspecting user which leads to executing malicious script code.  This may allow the attacker steal cookie-based authentication credentials and comprise user's account then launch other attacks.

CVSS v3
5.4
EG Score
5.4(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: 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
Severity54% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
6%
KEV
Not listed

Published

March 19, 2026

Last Modified

June 17, 2026

Advisory Details (1)

Auto-updated Aug 6, 2026
No patch confirmed yet.
generic

Security Bulletin: HCL Connections Security Update for Cross Site Scripting Vulnerability (CVE-2026-21788) - Customer Support

https://support.hcl-software.com/csm?id=kb_article&sysparm_article=KB0129107

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 4× in last 7d / 20× 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. 2026-09-18 19:27 UTCEPSS rescore
  2. 2026-09-16 14:07 UTCEPSS rescore
  3. 2026-09-16 05:15 UTCEPSS rescore
  4. 2026-09-13 16:47 UTCEPSS rescore
  5. 2026-09-12 15:01 UTCEPSS rescore
  6. 2026-09-10 09:34 UTCEPSS rescore
  7. 2026-09-08 22:00 UTCEPSS rescore
  8. 2026-09-07 16:01 UTCEPSS rescore
  9. 2026-09-06 13:47 UTCEPSS rescore
  10. 2026-09-06 13:47 UTCEPSS rescore
  11. 2026-09-04 05:06 UTCEPSS rescore
  12. 2026-09-01 13:53 UTCEPSS rescore
  13. 2026-09-01 04:39 UTCEPSS rescore
  14. 2026-08-30 19:17 UTCEPSS rescore
  15. 2026-08-30 01:22 UTCEPSS rescore
  16. 2026-08-28 21:41 UTCEPSS rescore
  17. 2026-08-27 14:25 UTCEPSS rescore
  18. 2026-08-26 14:46 UTCEPSS rescore
  19. 2026-08-25 13:48 UTCEPSS rescore
  20. 2026-08-21 23:49 UTCEPSS rescore
  21. 2026-08-20 22:55 UTCEPSS rescore
  22. 2026-08-19 17:03 UTCEPSS rescore
  23. 2026-08-18 13:48 UTCEPSS rescore
  24. 2026-08-17 13:47 UTCEPSS rescore
  25. 2026-08-16 14:56 UTCEPSS rescore
Show 38 more
  1. 2026-08-16 11:12 UTCEG score recompute
  2. 2026-08-16 11:12 UTCGHSA enrichment
  3. 2026-08-16 02:14 UTCEPSS rescore
  4. 2026-08-15 01:30 UTCEPSS rescore
  5. 2026-08-14 07:21 UTCEG score recompute
  6. 2026-08-14 07:21 UTCGHSA enrichment
  7. 2026-08-13 22:00 UTCEPSS rescore
  8. 2026-08-12 23:01 UTCEG score recompute
  9. 2026-08-12 23:01 UTCGHSA enrichment
  10. 2026-08-12 13:50 UTCEPSS rescore
  11. 2026-08-11 21:29 UTCEG score recompute
  12. 2026-08-11 21:29 UTCGHSA enrichment
  13. 2026-08-11 13:42 UTCEPSS rescore
  14. 2026-08-11 00:00 UTCEPSS rescore
  15. 2026-08-10 08:27 UTCEG score recompute
  16. 2026-08-10 08:27 UTCGHSA enrichment
  17. 2026-08-09 13:46 UTCEPSS rescore
  18. 2026-08-09 06:55 UTCEG score recompute
  19. 2026-08-09 06:55 UTCGHSA enrichment
  20. 2026-08-08 16:37 UTCEPSS rescore
  21. 2026-08-07 17:26 UTCEG score recompute
  22. 2026-08-07 17:26 UTCGHSA enrichment
  23. 2026-08-06 13:46 UTCEPSS rescore
  24. 2026-08-06 01:35 UTCEG score recompute
  25. 2026-08-06 01:35 UTCGHSA enrichment
  26. 2026-08-05 19:17 UTCEPSS rescore
  27. 2026-08-04 15:10 UTCEPSS rescore
  28. 2026-08-04 10:38 UTCEPSS rescore
  29. 2026-08-04 00:43 UTCEG score recompute
  30. 2026-08-04 00:43 UTCGHSA enrichment
  31. 2026-08-03 10:35 UTCEPSS rescore
  32. 2026-08-02 16:36 UTCEG score recompute
  33. 2026-08-02 16:36 UTCGHSA enrichment
  34. 2026-08-02 02:26 UTCEPSS rescore
  35. 2026-08-01 04:15 UTCEPSS rescore
  36. 2026-07-30 01:30 UTCEPSS rescore
  37. 2026-07-27 14:38 UTCEG score recompute
  38. 2026-07-27 14:38 UTCGHSA enrichment

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-21788?
CVE-2026-21788 is a medium vulnerability published on March 19, 2026. HCL Connections is vulnerable to a cross-site scripting attack where an attacker may leverage this issue to execute arbitrary script code in the browser of an unsuspecting user which leads to executing malicious script code. This may allow the attacker steal cookie-based authentication credentials…
When was CVE-2026-21788 disclosed?
CVE-2026-21788 was first published in the National Vulnerability Database on March 19, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-21788 actively exploited?
CVE-2026-21788 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 94.0% of all scored CVEs.
What is the CVSS score of CVE-2026-21788?
CVE-2026-21788 has a CVSS v3 base score of 5.4 (NVD).
How do I remediate CVE-2026-21788?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-21788, 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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