How severe is CVE-2020-5616?

CVE-2020-5616 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-5616 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-5616?

CVE-2020-5616 primarily affects Calendar01 Project Calendar01. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-5616?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2020-5616 published?

CVE-2020-5616 was published on 2020-08-04 and last updated on 2026-06-17.

CVE-2020-5616

CVE-2020-5616 is a critical-severity vulnerability in Calendar01 Project Calendar01 with a CVSS 3.x base score of 9.8. 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-287.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 3% (86th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Calendar01 Project Calendar01
Published: 2020-08-04
Last modified: 2026-06-17

Description

[Calendar01], [Calendar02], [PKOBO-News01], [PKOBO-vote01], [Telop01], [Gallery01], [CalendarForm01], and [Link01] [Calendar01] free edition ver1.0.0, [Calendar02] free edition ver1.0.0, [PKOBO-News01] free edition ver1.0.3 and earlier, [PKOBO-vote01] free edition ver1.0.1 and earlier, [Telop01] free edition ver1.0.0, [Gallery01] free edition ver1.0.3 and earlier, [CalendarForm01] free edition ver1.0.3 and earlier, and [Link01] free edition ver1.0.0 allows remote attackers to bypass authentication and log in to the product with administrative privileges via unspecified vectors.

Frequently asked questions

What is CVE-2020-5616?: [Calendar01], [Calendar02], [PKOBO-News01], [PKOBO-vote01], [Telop01], [Gallery01], [CalendarForm01], and [Link01] [Calendar01] free edition ver1.0.0, [Calendar02] free edition ver1.0.0, [PKOBO-News01] free edition ver1.0.3 and earlier, [PKOBO-vote01] free edition ver1.0.1 and earlier, [Telop01] free edition ver1.0.0, [Gallery01] free edition ver1.0.3 and earlier, [CalendarForm01] free edition ver1.0.3 and earlier, and [Link01] free edition ver1.0.0 allows remote attackers to bypass authentication and log in to the product with administrative privileges via unspecified vectors.
How severe is CVE-2020-5616?: CVE-2020-5616 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-5616 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-5616?: CVE-2020-5616 primarily affects Calendar01 Project Calendar01. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-5616?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2020-5616 published?: CVE-2020-5616 was published on 2020-08-04 and last updated on 2026-06-17.

References

Affected products (8)

cpe:2.3:a:calendar01_project:calendar01:1.0.0:*:*:*:free:*:*:*
cpe:2.3:a:calendar02_project:calendar02:1.0.0:*:*:*:free:*:*:*
cpe:2.3:a:calendarform01_project:calendarform01:*:*:*:*:free:*:*:*
cpe:2.3:a:gallery01_project:gallery01:*:*:*:*:free:*:*:*
cpe:2.3:a:link01_project:link01:1.0.0:*:*:*:free:*:*:*
cpe:2.3:a:pkobo-news01_project:pkobo-news01:*:*:*:*:free:*:*:*
cpe:2.3:a:pkobo-vote01_project:pkobo-vote01:*:*:*:*:free:*:*:*
cpe:2.3:a:telop01_project:telop01:1.0.0:*:*:*:free:*:*:*

More vulnerabilities in Calendar01 Project Calendar01

CVE-2020-5615 — High (CVSS 8.8): Cross-site request forgery (CSRF) vulnerability in [Calendar01] free edition ver1.0.0 and [Calendar02] free edition…
CVE-2021-20725 — Medium (CVSS 6.1): Reflected cross-site scripting vulnerability in the admin page of [Calendar01] free edition ver1.0.1 and earlier allows…

All CVEs affecting Calendar01 Project Calendar01 →

Other CWE-287 (Improper Authentication) vulnerabilities

CVE-2026-45480 — Critical (CVSS 10.0): Improper authentication in Azure Active Directory allows an unauthorized attacker to elevate privileges over a network.
CVE-2026-46389 — Critical (CVSS 10.0): UDS Identity Config builds the Keycloak configuration image (realm, plugins, theme, truststore, JARs) consumed by UDS…
CVE-2026-10611 — Critical (CVSS 10.0): An authentication bypass vulnerability exists in MISP when LDAP mixed authentication is enabled with OTP enforcement.…
CVE-2026-47280 — Critical (CVSS 10.0): Improper authentication in Azure Resource Manager (ARM) allows an unauthorized attacker to elevate privileges over a…
CVE-2026-42822 — Critical (CVSS 10.0): Improper authentication in Azure Local Disconnected Operations allows an unauthorized attacker to elevate privileges…
CVE-2026-20182 — Critical (CVSS 10.0): May 2026: This security advisory provides the details and fix information for a vulnerability that was discovered and…

Browse all CWE-287 (Improper Authentication) vulnerabilities →