CVE-2025-27914: An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0 and 10.1

Routine

MEDIUM 5.4UPGRADE

CVE-2025-27914 is a medium-severity flaw (CVSS 5.4) affecting collaboration. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0 and 10.1. A Reflected Cross-Site Scripting (XSS) vulnerability exists in the /h/rest endpoint, allowing authenticated attackers to inject and execute arbitrary JavaScript in a victim's session. Exploitation requires a valid auth token and involves a crafted URL with manipulated query parameters that triggers XSS when accessed by a victim.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.3% (top 79%)
CISA exploited list	No
Weakness	CWE-79
Published	2025-03-12
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: zimbra

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

Am I affected?

Timeline

2025-03-12 15:15 UTCPublished CVE record published
2026-06-17 09:04 UTCUpdated Record last modified

zimbra collaboration UPGRADE

Affected: >= 10.0.0 and < 10.0.11 · 9.0.0 · 10.1.0

Fixed in: 10.0.11

Safe to downgrade to: a release before 9.0.0

1. Check installed version

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

2. UPGRADE to 10.0.11 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade collaboration

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade collaboration

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 9.0.0 (Debian / Ubuntu)

apt-cache madison collaboration sudo apt install collaboration=<VERSION_BEFORE_9.0.0> sudo apt-mark hold collaboration

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list collaboration sudo dnf downgrade collaboration-<VERSION_BEFORE_9.0.0> sudo dnf versionlock add collaboration

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-2025-27914?

collaboration: upgrade to 10.0.11. Exact commands for each OS are on this page.

Is CVE-2025-27914 being exploited?

CVE-2025-27914 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-2025-27914 affect?

CVE-2025-27914 affects collaboration. Severity is medium (CVSS 5.4). An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0 and 10.1. A Reflected Cross-Site Scripting (XSS) vulnerability exists in the /h/rest endpoint, allowing authenticated attackers to inject and execute arbitrary JavaScript in

How urgent is CVE-2025-27914?

Priority 24/100. No elevated risk signals yet.

Software pages

Zimbra vulnerabilities

Related CVEs

CVE-2025-67809 MEDIUM 4.7 UPGRADE An issue was discovered in Zimbra Collaboration (ZCS) 10.0 and 10.1
CVE-2024-45515 MEDIUM 6.1 UPGRADE An issue was discovered in Zimbra Collaboration (ZCS) through 10.1
CVE-2024-33536 MEDIUM 5.4 UPGRADE An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0
CVE-2024-33535 HIGH 7.5 UPGRADE An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0
CVE-2024-33533 MEDIUM 5.4 UPGRADE An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0, issue 1 of 2

References

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