CVE-2026-93628

mediumpriority · track · 0EPSS 0.003 · 19 %ile
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
0.27% (19th) EPSS
CVSS 5.3 · medium
Is it mine?
0 products
Check your exposure
Who says so?
— sources

EPSS · scored 2026-10-27

An attendee authentication vulnerability in the email calendar processing of Zimbra Collaboration Suite (ZCS) allows an unauthenticated sender to forge another attendee's response to an existing meeting. Zimbra passes a null sender identity when processing iCalendar REPLY components, causing the attendee authorization filter to be skipped. An attacker who knows the meeting UID, organizer address and attendee address can send a non-outdated reply that changes the attendee's participation status in the organizer's calendar. The change occurs automatically during delivery without organizer or attendee interaction. ZCS 10.1.16 and 10.1.21 are affected.

01

cvss

Technical severity, 0–10. One row per scoring source.

5.3
010

base score 0–10 · higher = more severe · hover a vector to decode

v3.15.3mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:Nsecondary · cve@rapid7.comexploitability 3.9 · impact 1.4
v3.14.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:Usecondary · CVSS-BT (t0sche)
02

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-290US
03

affected products

Products and version ranges known to be affected.

No affected products recorded.

04

sources

Which sources assert this record, and when.

NVDCVE.orgMITRE
published 2026-10-23modified 2026-10-23
05

references (2) nvd

External citations — patches, advisories, analysis.

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