Cross-site scripting (XSS) vulnerability in the ZmMailMsgView.getAttachmentLinkHtml function in Zimbra Collaboration Suite (ZCS) before 8.7…

published 2018-03-27 8 y ago modified 2026-10-01 38 d ago also EUVD-2018-18627

cvss: 6.1; version 3.1, CNA
cisa kev: Exploited; added 2022-04-19, used in ransomware
epss: 29.8%; EPSS 29.8% chance of exploitation in 30 days, percentile 98%
public exploits: 0; none known, plus a Nuclei check

Cross-site scripting (XSS) vulnerability in the ZmMailMsgView.getAttachmentLinkHtml function in Zimbra Collaboration Suite (ZCS) before 8.7 Patch 1 and 8.8.x before 8.8.7 might allow remote attackers to inject arbitrary web script or HTML via a Content-Location header in an email attachment.

Patch / fix

cisa required action Apply updates per vendor instructions.

fixed in 1

synacor zimbra_collaboration_suite 8.7.0

Timeline

2018-03-27 Published
2022-04-19 Added to CISA KEV
2022-05-10 CISA patch deadline
2026-08-13 CISA SSVC: exploitation active

Known exploited

Added: 4 y ago (2022-04-19)
Patch by: 2022-05-10 (4 y ago)
Ransomware: Known to be used in ransomware campaigns
Required action: Apply updates per vendor instructions.
Vendor, product: Synacor, Zimbra Collaboration Suite (ZCS)
CISA name: Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting (XSS) Vulnerability

CISA SSVC

Exploitation: Active, exploited in the wild
Automatable: no
Technical impact: total
Assessed: 2 mo ago (2026-08-13)

Exploit prediction

29.76% chance of exploitation in the next 30 days, higher than 98% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

Nuclei template Zimbra Collaboration Suite - Cross-site Scripting nuclei detection template
securify.nl https://www.securify.nl/advisory/SFY20180101/cross-site-scripting-vulnerability-in-zimbra-collaboration-suite-due-to-the-way-it-handles-attachment-links.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CISA ADP	3.1	6.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD	3.1	6.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CNA	3.1	6.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD	2.0	4.3	AV:N/AC:M/Au:N/C:N/I:P/A:N

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation

References

securify.nl /advisory/SFY20180101/cross-site-scripting-vulnerability-in-zimbra-collaboration-suite-due-to-the-way-it-handl
exploit, third-party-advisory
wiki.zimbra.com /wiki/Zimbra_Security_Advisories
vendor-advisory
seclists.org /fulldisclosure/2018/Mar/52
mailing-list, third-party-advisory
wiki.zimbra.com /wiki/Zimbra_Releases/8.8.7
permissions-required
bugzilla.zimbra.com /show_bug.cgi?id=108786
broken-link, issue-tracking, permissions-required
securityfocus.com /archive/1/541891/100/0/threaded
mailing-list, broken-link, third-party-advisory, vdb-entry
cisa.gov /known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-6882
government-resource, us-government-resource

Sources

CVE List CVE-2018-6882
NVD CVE-2018-6882

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary