CVE-2020-5615: Cross-site request forgery (CSRF) vulnerability in [Calendar01] free edition ver1.0.0 and [Calendar02] free ed

This month

HIGH 8.8DOWNGRADEDOWNGRADE

CVE-2020-5615 is a high-severity flaw (CVSS 8.8) affecting calendar01, calendar02. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Cross-site request forgery (CSRF) vulnerability in [Calendar01] free edition ver1.0.0 and [Calendar02] free edition ver1.0.0 allows remote attackers to hijack the authentication of administrators via unspecified vectors.

Why this priority

High severity

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.7% (top 47%)
CISA exploited list	No
Weakness	CWE-352
Published	2020-08-04
Last modified	2026-06-17

Publisher (CNA): JPCERT/CC · Vendor: calendar01 project · calendar02 project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2020-08-04 02:15 UTCPublished CVE record published
2026-06-17 03:21 UTCUpdated Record last modified

calendar01 project calendar01 DOWNGRADE

Affected: 1.0.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.0.0

1. Check installed version

apt-cache policy calendar01 || rpm -q calendar01 || calendar01 --version

2. No fixed release: DOWNGRADE to a release before 1.0.0 (Debian / Ubuntu)

apt-cache madison calendar01 sudo apt install calendar01=<VERSION_BEFORE_1.0.0> sudo apt-mark hold calendar01

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list calendar01 sudo dnf downgrade calendar01-<VERSION_BEFORE_1.0.0> sudo dnf versionlock add calendar01

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

calendar02 project calendar02 DOWNGRADE

Affected: 1.0.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.0.0

1. Check installed version

apt-cache policy calendar02 || rpm -q calendar02 || calendar02 --version

2. No fixed release: DOWNGRADE to a release before 1.0.0 (Debian / Ubuntu)

apt-cache madison calendar02 sudo apt install calendar02=<VERSION_BEFORE_1.0.0> sudo apt-mark hold calendar02

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list calendar02 sudo dnf downgrade calendar02-<VERSION_BEFORE_1.0.0> sudo dnf versionlock add calendar02

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2020-5615?

calendar01: downgrade or apply the listed mitigation; calendar02: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-5615 being exploited?

CVE-2020-5615 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2020-5615 affect?

CVE-2020-5615 affects calendar01, calendar02. Severity is high (CVSS 8.8). Cross-site request forgery (CSRF) vulnerability in [Calendar01] free edition ver1.0.0 and [Calendar02] free edition ver1.0.0 allows remote attackers to hijack the authentication of administrators via unspecified vectors.

How urgent is CVE-2020-5615?

Priority 44/100. High severity

Related CVEs

CVE-2021-20725 MEDIUM 6.1 UPGRADE Reflected cross-site scripting vulnerability in the admin page of [Calendar01] free edition ver1.0.1 and earli
CVE-2020-5616 CRITICAL 9.8 DOWNGRADE DOWNGRADE [Calendar01], [Calendar02], [PKOBO-News01], [PKOBO-vote01], [Telop01], [Gallery01], [CalendarForm01], and [Lin

References

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