What products are affected by CVE-2025-68645?

CVE-2025-68645 affects Synacor Zimbra Collaboration Suite (ZCS). Refer to the vendor advisory and NVD record for affected versions.

Is there a public exploit for CVE-2025-68645?

Yes. Public exploit code or proof-of-concept has been identified for CVE-2025-68645. This lowers the barrier for exploitation and increases the urgency of patching. Organizations should prioritize remediation immediately.

What is the EPSS score for CVE-2025-68645?

CVE-2025-68645 has an EPSS score of 47.6%, placing it in the 98th percentile. This means it has a 47.6% probability of being exploited in the next 30 days, higher than 98% of all known vulnerabilities. EPSS (Exploit Prediction Scoring System) is maintained by FIRST and uses real-world threat data to estimate exploitation likelihood.

Actively Exploited — CISA KEV

CVE-2025-68645: Synacor Zimbra Collaboration Suite (ZCS) High-Severity Vulnerability

Severity: High | CVSS 3.1: 8.8 | Published: 2025-12-22 | KEV Added: 2026-01-22

What is 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.

Technical Analysis

Weakness Classification

This vulnerability is classified as CWE-98.

Attack Vector Breakdown

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Impact Analysis

This vulnerability is exploitable over the network, meaning any system reachable via the internet or internal network is potentially at risk without physical access. The attack complexity is low, meaning exploitation does not depend on specialized conditions or race windows. Successful exploitation can result in full confidentiality breach (complete data disclosure), complete integrity compromise (data modification or code execution), total availability loss (denial of service).

Exploitation Probability (EPSS): 47.6% chance of exploitation in the next 30 days (98th percentile). This is a significantly elevated exploitation probability — prioritize patching.

Exploit Availability

Public exploit code or proof-of-concept is available for CVE-2025-68645. This significantly increases the risk of exploitation, as attackers can use or adapt existing exploit code rather than developing their own. A public exploit reference has been identified. Organizations should treat this as an urgent patching priority.

Is CVE-2025-68645 being exploited?

Yes. CVE-2025-68645 is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, restricted to CVEs with confirmed active exploitation in the wild. CISA added this vulnerability on 2026-01-22. Inclusion in KEV triggers the patching mandate under BOD 22-01 for U.S. federal civilian agencies, with a remediation deadline of 2026-02-12. Additionally, public exploit code is available, which lowers the barrier for attackers.

How to fix CVE-2025-68645

Apply the security update issued by Synacor for Zimbra Collaboration Suite (ZCS). If an immediate patch is not possible, consult the vendor advisory for mitigation guidance, restrict network exposure of the affected service, and monitor logs for indicators of exploitation. CISA's Known Exploited Vulnerabilities catalog requires U.S. federal agencies to remediate this vulnerability by the due date shown below under Binding Operational Directive 22-01. Private organizations should treat KEV entries as priority-one patches because active exploitation has been confirmed in the wild.

Related Vulnerabilities

Other actively exploited vulnerabilities affecting Zimbra Collaboration Suite (ZCS) or sharing the same weakness (CWE-98):

CVE-2025-48700 (Medium 6.1) [same product] — An issue was discovered in Zimbra Collaboration (ZCS) 8.8.15 and 9.0 and 10.0…
CVE-2025-66376 (High 7.2) [same product] — Zimbra Collaboration (ZCS) 10 before 10.0.18 and 10.1 before 10.1.13 allows…
CVE-2025-27915 (Unknown N/A) [same product] — Synacor Zimbra Collaboration Suite (ZCS) contains a cross-site scripting…
CVE-2019-9621 (High 7.5) [same product] — Zimbra Collaboration Suite before 8.6 patch 13, 8.7.x before 8.7.11 patch 10…
CVE-2024-27443 (Unknown N/A) [same product] — Zimbra Collaboration contains a cross-site scripting (XSS) vulnerability in…

Frequently asked questions

Is CVE-2025-68645 critical?

CVE-2025-68645 has a CVSS 3.1 base score of 8.8 — High severity. It should be treated as a priority patch, especially given the active exploitation confirmed by CISA. The availability of public exploit code further increases the urgency.

Is CVE-2025-68645 being actively exploited?

Yes — CISA added CVE-2025-68645 to the Known Exploited Vulnerabilities catalog on 2026-01-22. Inclusion in KEV means CISA has confirmed in-the-wild exploitation. Public exploit code has also been identified, making exploitation accessible to a broader range of threat actors.

How do I patch CVE-2025-68645?

Apply the security update from Synacor for Zimbra Collaboration Suite (ZCS). Federal agencies must remediate by 2026-02-12 under BOD 22-01.

What type of vulnerability is CVE-2025-68645?

CVE-2025-68645 is classified under CWE-98.

What is the CVSS score for CVE-2025-68645?

CVE-2025-68645 has a CVSS 3.1 base score of 8.8, classifying it as High severity. The attack vector is Network, attack complexity is Low, and no privileges are required.