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TI-2025-20639 Aliases CVE-2025-27915GHSA-5rg8-g76j-7fw7

An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0 and 10.1.

Priority HIGH 84Exploited in the wildCWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Required
Attack complexity
Low
Impact type
Cross-site scripting
Confidentiality · integrity · availability
Low · Low · None
Fix status
No fix listed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-79.

Summary

An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0 and 10.1. A stored cross-site scripting (XSS) vulnerability exists in the Classic Web Client due to insufficient sanitization of HTML content in ICS files. When a user views an e-mail message containing a malicious ICS entry, its embedded JavaScript executes via an ontoggle event inside a <details> tag. This allows an attacker to run arbitrary JavaScript within the victim's session, potentially leading to unauthorized actions such as setting e-mail filters to redirect messages to an attacker-controlled address. As a result, an attacker can perform unauthorized actions on the victim's account, including e-mail redirection and data exfiltration.

Why it matters now

Exploitation Active In CISA KEV since 2025-10-07CISA due date 2025-10-28
EPSS 0.04064 90th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Active
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
——all versions—No fix listedCNA
  • — Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 46

CPEVersionsRoleVendor
cpe:2.3:a:synacor:zimbra_collaboration_suite:*:*:*:*:*:*:*:*10.0.0 to before 10.0.13; 10.1.0 to before 10.1.5VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:-:*:*:*:*:*:*9.0.0VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p1:*:*:*:*:*:*9.0.0 p1VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p10:*:*:*:*:*:*9.0.0 p10VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p11:*:*:*:*:*:*9.0.0 p11VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p12:*:*:*:*:*:*9.0.0 p12VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p13:*:*:*:*:*:*9.0.0 p13VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p14:*:*:*:*:*:*9.0.0 p14VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p15:*:*:*:*:*:*9.0.0 p15VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p16:*:*:*:*:*:*9.0.0 p16VulnerableSynacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:*:*:*:*:*:*:*:* Versions 10.0.0 to before 10.0.13; 10.1.0 to before 10.1.5 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:-:*:*:*:*:*:* Versions 9.0.0 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p1:*:*:*:*:*:* Versions 9.0.0 p1 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p10:*:*:*:*:*:* Versions 9.0.0 p10 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p11:*:*:*:*:*:* Versions 9.0.0 p11 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p12:*:*:*:*:*:* Versions 9.0.0 p12 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p13:*:*:*:*:*:* Versions 9.0.0 p13 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p14:*:*:*:*:*:* Versions 9.0.0 p14 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p15:*:*:*:*:*:* Versions 9.0.0 p15 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p16:*:*:*:*:*:* Versions 9.0.0 p16 Vulnerable ·Synacor
Show 36 more CPE
CPEVersionsRoleVendor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p17:*:*:*:*:*:*9.0.0 p17VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p18:*:*:*:*:*:*9.0.0 p18VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p19:*:*:*:*:*:*9.0.0 p19VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p2:*:*:*:*:*:*9.0.0 p2VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p20:*:*:*:*:*:*9.0.0 p20VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p21:*:*:*:*:*:*9.0.0 p21VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p22:*:*:*:*:*:*9.0.0 p22VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p23:*:*:*:*:*:*9.0.0 p23VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p24:*:*:*:*:*:*9.0.0 p24VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p24.1:*:*:*:*:*:*9.0.0 p24.1VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p25:*:*:*:*:*:*9.0.0 p25VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p26:*:*:*:*:*:*9.0.0 p26VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p27:*:*:*:*:*:*9.0.0 p27VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p28:*:*:*:*:*:*9.0.0 p28VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p29:*:*:*:*:*:*9.0.0 p29VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p3:*:*:*:*:*:*9.0.0 p3VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p30:*:*:*:*:*:*9.0.0 p30VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p31:*:*:*:*:*:*9.0.0 p31VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p32:*:*:*:*:*:*9.0.0 p32VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p33:*:*:*:*:*:*9.0.0 p33VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p34:*:*:*:*:*:*9.0.0 p34VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p35:*:*:*:*:*:*9.0.0 p35VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p36:*:*:*:*:*:*9.0.0 p36VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p37:*:*:*:*:*:*9.0.0 p37VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p38:*:*:*:*:*:*9.0.0 p38VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p39:*:*:*:*:*:*9.0.0 p39VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p4:*:*:*:*:*:*9.0.0 p4VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p40:*:*:*:*:*:*9.0.0 p40VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p41:*:*:*:*:*:*9.0.0 p41VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p42:*:*:*:*:*:*9.0.0 p42VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p43:*:*:*:*:*:*9.0.0 p43VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p5:*:*:*:*:*:*9.0.0 p5VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p6:*:*:*:*:*:*9.0.0 p6VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p7:*:*:*:*:*:*9.0.0 p7VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p8:*:*:*:*:*:*9.0.0 p8VulnerableSynacor
cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p9:*:*:*:*:*:*9.0.0 p9VulnerableSynacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p17:*:*:*:*:*:* Versions 9.0.0 p17 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p18:*:*:*:*:*:* Versions 9.0.0 p18 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p19:*:*:*:*:*:* Versions 9.0.0 p19 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p2:*:*:*:*:*:* Versions 9.0.0 p2 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p20:*:*:*:*:*:* Versions 9.0.0 p20 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p21:*:*:*:*:*:* Versions 9.0.0 p21 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p22:*:*:*:*:*:* Versions 9.0.0 p22 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p23:*:*:*:*:*:* Versions 9.0.0 p23 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p24:*:*:*:*:*:* Versions 9.0.0 p24 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p24.1:*:*:*:*:*:* Versions 9.0.0 p24.1 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p25:*:*:*:*:*:* Versions 9.0.0 p25 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p26:*:*:*:*:*:* Versions 9.0.0 p26 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p27:*:*:*:*:*:* Versions 9.0.0 p27 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p28:*:*:*:*:*:* Versions 9.0.0 p28 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p29:*:*:*:*:*:* Versions 9.0.0 p29 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p3:*:*:*:*:*:* Versions 9.0.0 p3 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p30:*:*:*:*:*:* Versions 9.0.0 p30 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p31:*:*:*:*:*:* Versions 9.0.0 p31 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p32:*:*:*:*:*:* Versions 9.0.0 p32 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p33:*:*:*:*:*:* Versions 9.0.0 p33 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p34:*:*:*:*:*:* Versions 9.0.0 p34 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p35:*:*:*:*:*:* Versions 9.0.0 p35 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p36:*:*:*:*:*:* Versions 9.0.0 p36 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p37:*:*:*:*:*:* Versions 9.0.0 p37 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p38:*:*:*:*:*:* Versions 9.0.0 p38 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p39:*:*:*:*:*:* Versions 9.0.0 p39 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p4:*:*:*:*:*:* Versions 9.0.0 p4 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p40:*:*:*:*:*:* Versions 9.0.0 p40 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p41:*:*:*:*:*:* Versions 9.0.0 p41 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p42:*:*:*:*:*:* Versions 9.0.0 p42 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p43:*:*:*:*:*:* Versions 9.0.0 p43 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p5:*:*:*:*:*:* Versions 9.0.0 p5 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p6:*:*:*:*:*:* Versions 9.0.0 p6 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p7:*:*:*:*:*:* Versions 9.0.0 p7 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p8:*:*:*:*:*:* Versions 9.0.0 p8 Vulnerable ·Synacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:9.0.0:p9:*:*:*:*:*:* Versions 9.0.0 p9 Vulnerable ·Synacor

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2025-10-07 Added to CISA KEV
  2. 2026-10-02 Threatist record created from CVE-2025-27915
  3. 2026-10-03 Alias added: GHSA-5rg8-g76j-7fw7

References

Exploit 1

Other 4

  • TI-2024-30554 The postjournal service in Zimbra Collaboration (ZCS) before 8.8.15 Patch 46, 9 before… KEVCVSS 3.1CRITICAL 10.0
  • TI-2022-19841 An issue was discovered in Zimbra Collaboration (ZCS) 8.8.15 and 9.0. KEVCVSS 3.1CRITICAL 9.8
  • TI-2022-17239 Zimbra Collaboration Suite (ZCS) 8.8.15 and 9.0 has mboximport functionality that… KEVCVSS 3.1CRITICAL 9.8
  • TI-2022-10792 Zimbra Collaboration (aka ZCS) 8.8.15 and 9.0 allows an unauthenticated attacker to… KEVCVSS 3.1CRITICAL 9.8
  • TI-2020-06312 Zimbra Collaboration Suite (ZCS) before 8.8.15 Patch 7 allows SSRF when WebEx zimlet is… KEVCVSS 3.1CRITICAL 9.8
  • TI-2019-07076 mailboxd component in Synacor Zimbra Collaboration Suite 8.7.x before 8.7.11p10 has an… KEVCVSS 3.1CRITICAL 9.8
See all 96 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences