What is CVE-2025-68645?

CVE-2025-68645 is a high-severity vulnerability in Synacor Zimbra Collaboration Suite, classified under PHP Remote File Inclusion. CVSS score: 8.8/10. Published 2025-12-22.

How severe is CVE-2025-68645?

High severity. CVSS v3 base score is 8.8 out of 10.

Is CVE-2025-68645 known to be exploited?

Yes. CVE-2025-68645 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-01-22), indicating it is being actively exploited. 10 public proof-of-concept repositories are indexed.

Vulnerability in Synacor Zimbra Collaboration Suite

CVE-2025-68645

A Local File Inclusion (LFI) vulnerability exists in the Webmail Classic UI of Zimbra Collaboration (ZCS) 10.0 and 10.1 because of improper handling of user-supplied request parameters in the RestFilter servlet. An unauthenticated remote attacker can craft requests to the /h/rest endpoint to influence internal request dispatching, allowing inclusion of arbitrary files from the WebRoot directory.

Published 2025-12-22 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.489 (98.9th percentile), scored 2026-10-19.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 99th percentile — 98.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.489 · newest: 0.489 · change: 0.000

Affected products

Synacor Zimbra Collaboration Suite

Weakness classification (CWE)

CWE-98 — PHP Remote File Inclusion

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2026-01-22. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2026-02-12.

Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Public proof-of-concept exploits

References

wiki.zimbra.com/wiki/Security_Center (Release Notes, Vendor Advisory)
wiki.zimbra.com/wiki/Zimbra_Responsible_Disclosure_Policy (Product)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)

Frequently asked questions

What is CVE-2025-68645?: CVE-2025-68645 is a high-severity vulnerability in Synacor Zimbra Collaboration Suite, classified under PHP Remote File Inclusion. CVSS score: 8.8/10. Published 2025-12-22.
How severe is CVE-2025-68645?: High severity. CVSS v3 base score is 8.8 out of 10.
Is CVE-2025-68645 known to be exploited?: Yes. CVE-2025-68645 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-01-22), indicating it is being actively exploited. 10 public proof-of-concept repositories are indexed.