How severe is CVE-2026-21789?

CVE-2026-21789 has a CVSS 3.x base score of 4.6, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2026-21789 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (2nd percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-21789?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-21789 have an EU (EUVD) identifier?

Yes. CVE-2026-21789 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30798.

When was CVE-2026-21789 published?

CVE-2026-21789 was published on 2026-05-18 and last updated on 2026-06-17.

CVE-2026-21789

CVE-2026-21789 is a medium-severity vulnerability with a CVSS 3.x base score of 4.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-863.

Key facts

Severity: Medium (CVSS 3.x base score 4.6)
EPSS exploit prediction: 0% (2nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-30798
Weakness: CWE-863
Published: 2026-05-18
Last modified: 2026-06-17

Description

HCL Connections contains a broken access control vulnerability that may allow unauthorized user to update data in certain scenarios.

Frequently asked questions

What is CVE-2026-21789?: HCL Connections contains a broken access control vulnerability that may allow unauthorized user to update data in certain scenarios.
How severe is CVE-2026-21789?: CVE-2026-21789 has a CVSS 3.x base score of 4.6, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-21789 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (2nd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-21789?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-21789 have an EU (EUVD) identifier?: Yes. CVE-2026-21789 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30798.
When was CVE-2026-21789 published?: CVE-2026-21789 was published on 2026-05-18 and last updated on 2026-06-17.

References

https://support.hcl-software.com/csm?id=kb_article&sysparm_article=KB0129719

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