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VulnerabilityPublished Updated

CVE-2023-37580: Synacor Zimbra Collaboration Suite (ZCS) · Cross-site Scripting

Affects Synacor Zimbra Collaboration Suite (ZCS)Source CVE Database V5

0

Exploited in the wild · KEV due 17 Aug 2023 · public detection template (Nuclei) · 49% EPSS : upgrade to 8.8.15 now.

Data as of 26 Oct 2026, 15:59 UTC

CVSS 3.1 base score
6.1Medium
How severe the flaw is on the 0–10 CVSS scale.
KEV deadline
 US federal agencies must patch by this date; a sensible deadline for everyone else. Other KEV due dates
EPSS
49.0% chance of exploitation in 30 days – higher than 98% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 8.8.15
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

  1. Disclosed: evidence found.

    CVE published 31 Jul 2023

  2. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  3. Exploited in the wild: evidence found.

    Listed in CISA KEV 4 days before disclosure

  4. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

Timeline

  1. CVE ID reserved

    by MITRE Corporation

    , 24 days before disclosure

  2. , 4 days before disclosure

  3. CVE published

    on cve.org

    , t = 0

  4. KEV remediation due

    US federal deadline

    , 17 days after disclosure

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA KEV (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade Synacor Zimbra Collaboration Suite (ZCS) to 8.8.15.

Affected software

ProductAffectedFixed in
Synacor Zimbra Collaboration Suite (ZCS)Affected
  • <8.8.15
Fixed in
  • 8.8.15

Description

Zimbra Collaboration (ZCS) 8 before 8.8.15 Patch 41 allows XSS in the Zimbra Classic Web Client.

References

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