How severe is CVE-2026-21788?

CVE-2026-21788 has a CVSS 3.x base score of 5.4, 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-2026-21788 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (6th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-21788?

CVE-2026-21788 primarily affects Hcltech Connections. In total, 13 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-21788?

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

Does CVE-2026-21788 have an EU (EUVD) identifier?

Yes. CVE-2026-21788 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-13075.

When was CVE-2026-21788 published?

CVE-2026-21788 was published on 2026-03-19 and last updated on 2026-06-17.

CVE-2026-21788

CVE-2026-21788 is a medium-severity vulnerability in Hcltech Connections with a CVSS 3.x base score of 5.4. 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-79.

Key facts

Severity: Medium (CVSS 3.x base score 5.4)
EPSS exploit prediction: 0% (6th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-13075
Weakness: CWE-79
Affected product: Hcltech Connections
Published: 2026-03-19
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2026-21788?: 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.
How severe is CVE-2026-21788?: CVE-2026-21788 has a CVSS 3.x base score of 5.4, 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-2026-21788 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (6th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-21788?: CVE-2026-21788 primarily affects Hcltech Connections. In total, 13 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-21788?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-21788 have an EU (EUVD) identifier?: Yes. CVE-2026-21788 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-13075.
When was CVE-2026-21788 published?: CVE-2026-21788 was published on 2026-03-19 and last updated on 2026-06-17.

References

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

Affected products (13)

cpe:2.3:a:hcltech:connections:8.0:-:*:*:*:*:*:*
cpe:2.3:a:hcltech:connections:8.0:cumulative_release1:*:*:*:*:*:*
cpe:2.3:a:hcltech:connections:8.0:cumulative_release10:*:*:*:*:*:*
cpe:2.3:a:hcltech:connections:8.0:cumulative_release11:*:*:*:*:*:*
cpe:2.3:a:hcltech:connections:8.0:cumulative_release12:*:*:*:*:*:*
cpe:2.3:a:hcltech:connections:8.0:cumulative_release2:*:*:*:*:*:*
cpe:2.3:a:hcltech:connections:8.0:cumulative_release3:*:*:*:*:*:*
cpe:2.3:a:hcltech:connections:8.0:cumulative_release4:*:*:*:*:*:*
cpe:2.3:a:hcltech:connections:8.0:cumulative_release5:*:*:*:*:*:*
cpe:2.3:a:hcltech:connections:8.0:cumulative_release6:*:*:*:*:*:*
cpe:2.3:a:hcltech:connections:8.0:cumulative_release7:*:*:*:*:*:*
cpe:2.3:a:hcltech:connections:8.0:cumulative_release8:*:*:*:*:*:*
cpe:2.3:a:hcltech:connections:8.0:cumulative_release9:*:*:*:*:*:*

More vulnerabilities in Hcltech Connections

CVE-2020-4085 — Medium (CVSS 6.5): "HCL Connections is vulnerable to possible information leakage and could disclose sensitive information via stack trace…
CVE-2019-4209 — Medium (CVSS 6.1): HCL Connections v5.5, v6.0, and v6.5 contains an open redirect vulnerability which could be exploited by an attacker to…
CVE-2023-28018 — Medium (CVSS 5.5): HCL Connections is vulnerable to a denial of service, caused by improper validation on certain requests. Using a…
CVE-2020-4083 — Medium (CVSS 5.5): HCL Connections 6.5 is vulnerable to possible information leakage. Connections could disclose sensitive information via…
CVE-2024-30112 — Medium (CVSS 5.4): HCL Connections is vulnerable to a cross-site scripting attack where an attacker may leverage this issue to execute…
CVE-2023-28017 — Medium (CVSS 5.4): HCL Connections is vulnerable to a cross-site scripting attack where an attacker may leverage this issue to execute…

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