CVE-2022-24682
CVE-2022-24682 is a security flaw in Synacor Zimbra Collaborate Suite (ZCS), email and calendar software companies run on their own servers. Attackers can run their own code on Synacor Zimbra Collaborate Suite (ZCS). The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 25 Feb 2022, and says ransomware gangs have used it.[1]
Synacor Zimbra Collaborate Suite (ZCS) is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. Synacor has published a fix or advice.
Description
CISA calls it a cross-site scripting in Synacor Zimbra Collaborate Suite (ZCS). In its words: “Synacor Zimbra Collaboration Suite (ZCS) contains a cross-site scripting (XSS) vulnerability in the Calendar feature that allows an attacker to execute arbitrary code.”[1]
The CVE record adds: “An issue was discovered in the Calendar feature in Zimbra Collaboration Suite 8.8.x before 8.8.15 patch 30 (update 1), as exploited in the wild starting in December 2021. An attacker could place HTML containing executable JavaScript inside element attributes. This markup becomes unescaped, causing arbitrary markup to be injected into the document.”[2]
The underlying weakness is cross-site scripting (CWE-79), CWE-116, in MITRE’s list of common software weaknesses.
It scores 6.1 out of 10 on the Common Vulnerability Scoring System, which rates it medium, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record doesn’t list version ranges for it; Synacor’s advisory has them[3]. CISA names the product as Synacor Zimbra Collaborate Suite (ZCS).
Most families won’t have Synacor Zimbra Collaborate Suite (ZCS); it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 25 Feb 2022, 16 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 11 Mar 2022 to fix it.[1] CISA says ransomware gangs have used it.
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 31%. That’s in the top 2% of the flaws it scores.[4]
CISA assesses it as not automatable: each attack takes some work.
CISA doesn’t say who was attacked, or how.
Fix
Synacor has published a fix or advice.[3] CISA’s required action: “Apply updates per vendor instructions.”[1]
- Check whether you use it.Synacor Zimbra Collaborate Suite (ZCS) is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
- Send this page to your IT person.Ask them to confirm it’s fixed, or not in use. CISA gave US government agencies until 11 Mar 2022 to fix it.
- If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.
You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 6.1.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks, noting that ransomware gangs have used it.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 31%.[4] |
See also
Other Synacor flaws
- CVE-2026-73570, Synacor Zimbra Collaboration Suite (ZCS): OS command injection ·
- CVE-2025-48700, Synacor Zimbra Collaboration Suite (ZCS): cross-site scripting ·
- CVE-2025-66376, Synacor Zimbra Collaboration Suite (ZCS): cross-site scripting ·
- CVE-2020-7796, Synacor Zimbra Collaboration Suite: (ZCS) server-side request forgery ·
- CVE-2025-68645, Synacor Zimbra Collaboration Suite (ZCS): PHP remote file inclusion ·
Other cross-site scripting flaws
- CVE-2026-42897, Microsoft: exchange server cross-site scripting ·
- CVE-2025-68461, Roundcube Webmail: cross-site scripting ·
- CVE-2021-26829, OpenPLC ScadaBR: cross-site scripting ·
- CVE-2024-42009, Roundcube Webmail: cross-site scripting ·
- CVE-2024-11182, MDaemon Email Server: cross-site scripting (XSS) ·
Added the same day
- CVE-2017-8570, Microsoft Office: remote code execution ·
- CVE-2017-0222, Microsoft Internet Explorer: remote code execution ·
- CVE-2014-6352, Microsoft Windows: code injection ·
Every Synacor flaw on CISA’s list · Everything added in February 2022
References
- ^ Cybersecurity and Infrastructure Security Agency. “Synacor Zimbra Collaborate Suite (ZCS) Cross-Site Scripting Vulnerability”. Known Exploited Vulnerabilities Catalog, added 25 Feb 2022.
- ^ National Institute of Standards and Technology. “CVE-2022-24682 Detail”. National Vulnerability Database, published 9 Feb 2022.
- ^ Synacor. Advisories and fixes: blog.zimbra.com, wiki.zimbra.com, wiki.zimbra.com, wiki.zimbra.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.309, percentile 98.3, 31 Oct 2026.
- CVE Program. “CVE-2022-24682”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.