CVE-2022-26562: An issue in provider/libserver/ECKrbAuth.cpp of Kopano Core <= v11.0.2.51 contains an issue which allows attac

Q: How urgent is CVE-2022-26562?

Priority 65/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

CRITICAL 9.8REMOTEDOWNGRADE

CVE-2022-26562 is a critical-severity flaw (CVSS 9.8) affecting groupware core. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue in provider/libserver/ECKrbAuth.cpp of Kopano Core <= v11.0.2.51 contains an issue which allows attackers to authenticate even if the user account or password is expired. It also exists in the predecessor Zarafa Collaboration Platform (ZCP) in provider/libserver/ECPamAuth.cpp of Zarafa >= 6.30 (introduced between 6.30.0 RC1e and 6.30.8 final).

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

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

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.2% (top 18%)
CISA exploited list	No
Weakness	CWE-287
Published	2022-04-01
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: kopano

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

Am I affected?

Timeline

2022-04-01 20:15 UTCPublished CVE record published
2026-06-17 04:35 UTCUpdated Record last modified

kopano groupware core DOWNGRADE

Affected: 11.0.2.51

Fixed in: no fixed release known

Safe to downgrade to: a release before 11.0.2.51

1. Check installed version

apt-cache policy groupware-core || rpm -q groupware-core || groupware-core --version

2. No fixed release: DOWNGRADE to a release before 11.0.2.51 (Debian / Ubuntu)

apt-cache madison groupware-core sudo apt install groupware-core=<VERSION_BEFORE_11.0.2.51> sudo apt-mark hold groupware-core

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

dnf --showduplicates list groupware-core sudo dnf downgrade groupware-core-<VERSION_BEFORE_11.0.2.51> sudo dnf versionlock add groupware-core

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-2022-26562?

groupware core: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2022-26562 being exploited?

CVE-2022-26562 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-2022-26562 affect?

CVE-2022-26562 affects groupware core. Severity is critical (CVSS 9.8). An issue in provider/libserver/ECKrbAuth.cpp of Kopano Core <= v11.0.2.51 contains an issue which allows attackers to authenticate even if the user account or password is expired. It also exists in the predecessor Zarafa Collaboration Platf

How urgent is CVE-2022-26562?

Priority 65/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2021-28994 HIGH 7.5 UPGRADE UPGRADE kopano-ical (formerly zarafa-ical) in Kopano Groupware Core through 8.7.16, 9.x through 9.1.0, 10.x through 10

References

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