Threats / Synacor / CVE-2023-34192
CVE-2023-34192
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Synacor Zimbra Collaboration Suite (ZCS) vulnerability
Synacor Zimbra Collaboration Suite contains a cross-site scripting vulnerability in the /h/autoSaveDraft function that allows authenticated attackers to execute arbitrary code.
Verdict
Today item — known-exploited.
A reflected or stored XSS flaw enables authenticated users to inject malicious scripts, potentially compromising session integrity, stealing credentials, or performing unauthorized actions within the collaboration platform.
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
3 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-02-25).
Probability (EPSS)
EPSS 0.77266 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Synacor, Zimbra Collaboration Suite (ZCS). Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-79 Cross-site Scripting (XSS) — weakness family: Web / client.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft a malicious script payload and inject it into the autoSaveDraft function parameter.
Business
User sessions and sensitive collaboration data become vulnerable to hijacking and unauthorized access.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I execute arbitrary JavaScript in the victim's browser context when they interact with the affected function.
Business
Attackers can steal authentication tokens, session cookies, or sensitive information stored in the web application.
3
Lateral reach — past segmentation narrative 3
Attacker
I perform actions on behalf of the authenticated user, such as modifying emails, calendar entries, or contacts.
Business
Data integrity is compromised and business operations relying on Zimbra are disrupted through unauthorized modifications.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05