Is CVE-2026-45543 in the CISA KEV catalog?

No. CVE-2026-45543 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-45543?

CVE-2026-45543 has a CVSS v3 base score of 5.3 (MEDIUM).

What is the EPSS score for CVE-2026-45543?

CVE-2026-45543 has an EPSS score of 0.27% (19th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-45543?

Upgrade forms to 5.2.7 or later.

CVE & CISA-KEV Catalog

CVE-2026-45543

MEDIUM

5.3

CVSS v3

NVD

Description

Nextcloud is an open source content collaboration platform. From version 4.3.0 to before version 5.2.7, a removed collaborator retains unauthorized read access to uploaded respondent files for the affected form. The scope is limited to uploaded files for forms where that user previously had results access. This issue has been patched in version 5.2.7.

CWE-552

How to fix

Remediation Available

formsNVD

Affected:>= 4.3.0, < 5.2.7Fixed in:5.2.7CVE-2026-45543derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityLow

IntegrityNone

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Exploit Intelligence

0.27%probability of exploitation in 30 days

19thpercentile

Low risk: more likely to be exploited than 19% of all known CVEs.

References

Patch1

github.com

Vendor Advisory1

github.com

Other references1

hackerone.com

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-04.