How severe is CVE-2026-21790?

CVE-2026-21790 has a CVSS 3.x base score of 6.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2026-21790 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (5th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-21790?

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

Does CVE-2026-21790 have an EU (EUVD) identifier?

Yes. CVE-2026-21790 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-15002.

When was CVE-2026-21790 published?

CVE-2026-21790 was published on 2026-03-24 and last updated on 2026-06-17.

CVE-2026-21790

CVE-2026-21790 is a medium-severity vulnerability with a CVSS 3.x base score of 6.3. 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-346.

Key facts

Severity: Medium (CVSS 3.x base score 6.3)
EPSS exploit prediction: 0% (5th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-15002
Weakness: CWE-346
Published: 2026-03-24
Last modified: 2026-06-17

Description

HCL Traveler is susceptible to a weak default HTTP header validation vulnerability, which could allow an attacker to bypass additional authentication checks.

Frequently asked questions

What is CVE-2026-21790?: HCL Traveler is susceptible to a weak default HTTP header validation vulnerability, which could allow an attacker to bypass additional authentication checks.
How severe is CVE-2026-21790?: CVE-2026-21790 has a CVSS 3.x base score of 6.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2026-21790 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (5th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-21790?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-21790 have an EU (EUVD) identifier?: Yes. CVE-2026-21790 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-15002.
When was CVE-2026-21790 published?: CVE-2026-21790 was published on 2026-03-24 and last updated on 2026-06-17.

References

https://support.hcl-software.com/csm?id=kb_article&sysparm_article=KB0129139

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