CVE-2023-37580
MediumExploitedPublic exploitZimbra Collaboration (ZCS) 8 before 8.8.15 Patch 41 allows XSS in the Zimbra Classic Web Client.
Published Nov 17, 2023 · Updated Oct 8, 2026 · Also known as TR-23-0643
Key Facts
Patch immediately- CVE-2023-37580 is a medium-severity vulnerability (CVSS 6.1 v3.1) affecting Zimbra Collaboration Suite (Synacor).
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Jun 29, 2023. Public exploit code is available.
- EPSS estimates a 49% probability of exploitation in the next 30 days.
- Fixed versions are available, including Zimbra Collaboration Suite 8.8.15.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
6.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
EPSS (30-day exploit likelihood)
49%
Higher than 98.8% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2023-37580 brief as a PDF
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Description
Zimbra Collaboration (ZCS) 8 before 8.8.15 Patch 41 allows XSS in the Zimbra Classic Web Client.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Jul 27, 2023 | Aug 17, 2023 | Not reported |
| Industry KEV feed | Jun 29, 2023 | Aug 17, 2023 | Not reported |
| CIRCL KEV | Jul 27, 2023 | Aug 17, 2023 | Not reported |
| ENISA EUVD | Jul 27, 2023 | n/a | Not reported |
Required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Affected Products
14 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Zimbra Collaboration SuiteSynacor | 8.8.15-p11, 8.8.15-p26, 8.8.15-p3, 8.8.15-p30, 8.8.15-p31, 8.8.15-p32, 8.8.15-p33, 8.8.15-p34 | 8.8.15 |
Patched Releases
Zimbra Collaboration Suite
8.8.15
Timeline
Added to Industry KEV feed
Jun 29, 2023
Added to CISA KEV
Jul 27, 2023
Added to CIRCL KEV
Jul 27, 2023
Added to ENISA EUVD
Jul 27, 2023
Publicly disclosed
Nov 17, 2023
Last updated
Oct 8, 2026
Weakness Type
- CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
References
- advisoryVulnCheck exploitation report
- advisoryhttps://github.com/CVEProject/cvelistV5/tree/main/cves/2023/37xxx/CVE-2023-37580.json
- advisoryhttps://nvd.nist.gov/vuln/detail/CVE-2023-37580
- advisoryhttps://www.securityweek.com/zimbra-zero-day-exploited-to-hack-government-emails/
- advisoryUSOM advisory
FAQ
Common Questions.
Zimbra Collaboration (ZCS) 8 before 8.8.15 Patch 41 allows XSS in the Zimbra Classic Web Client.
Affected: Zimbra Collaboration Suite (Synacor) versions 8.8.15-p11, 8.8.15-p26, 8.8.15-p3, 8.8.15-p30, 8.8.15-p31, 8.8.15-p32, 8.8.15-p33, 8.8.15-p34. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Jun 29, 2023.
Yes. It was added on Jul 27, 2023 with a federal remediation due date of Aug 17, 2023.
Public exploit code is available.
Fixed versions are available, including Zimbra Collaboration Suite 8.8.15.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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