CVE-2023-34192: Synacor exploited

Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.

What it is

Cross Site Scripting vulnerability in Zimbra ZCS v.8.8.15 allows a remote authenticated attacker to execute arbitrary code via a crafted script to the /h/autoSaveDraft function.

Description quoted from the CVE record (assigned by mitre, published 2023-07-06).

Weakness: CWE-79 Improper Neutralization of Input During Web Page Generation (‘Cross-site Scripting’)

How it can be exploited

Exploitable over the network with low attack complexity needing low privileges and a user must take an action. Impact: confidentiality high, integrity high, availability high. CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

CISA assessment (SSVC): CISA assesses exploitation as active. Automatable: no. Technical impact: total.

On CISA KEV since: 2025-02-25
US federal deadline: 2025-03-18
Ransomware use: Not known

Public exploit evidence (Exploit Observer)

Also known as: BDU:2023-04305, CNNVD-202307-439, EUVD-2023-38291, GHSA-77v2-mcx8-5hqm

VEDAS cluster: VEDAS:FIREWEAVER

Exploit Observer links 6 pieces of public exploit code or detection modules that name this CVE or one of its aliases.

Exploit code and modules (6)

Code that names this CVE. A repository can be a working exploit, a scanner, a fake or malware; read it before running anything.

Vulnerability databases and vendor advisories (6)

Catalogue entries, not exploit evidence.

Vulnerability database or vendor advisory: https://euvd.enisa.europa.eu/enisa/EUVD-2023-38291
Vulnerability database or vendor advisory: https://github.com/advisories/GHSA-77v2-mcx8-5hqm
Vulnerability database or vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2023-34192
Vulnerability database or vendor advisory: https://osv.dev/vulnerability/CVE-2023-34192
Vulnerability database or vendor advisory: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-34192
Vulnerability database or vendor advisory: https://www.cnnvd.org.cn/home/globalSearch?keyword=CNNVD-202307-439

News (2)

53 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.

VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.

Live scores

EPSS: 0.773
very likely to be attacked soon
VEDAS: 0.986
strong exploit evidence
On CISA KEV: Yes, since 2025-02-25
Detection rule: Nuclei · Suricata

EPSS (chance of attack)

VEDAS (exploit evidence)

Thin horizontal line: the “likely” (EPSS 0.10) or “strong” (VEDAS 0.90) threshold. Shaded “no data” areas are periods when cve-scores did not publish.

Who is affected

Product	Affected	Not affected
Not stated	version n/a	Not stated

Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.

How to fix it

CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Vendor guidance:

How to detect it

Nuclei template (active check)

Zimbra ZCS V - Cross-Site Scripting
Cross Site Scripting vulnerability in Zimbra ZCS v.8.8.15 allows a remote authenticated attacker to execute arbitrary code via a crafted script to the /h/autoSaveDraft function.

Name and description quoted from the template, written by VEDAS.

The template sends 2 requests (POST /zimbra/, GET /h/autoSaveDraft?draftid=aaaaaaaaaaa%22%3E%3Cscript%3Ealert%28auocf...); it decides using status, word matchers. Severity in the template: critical. Marked as not yet verified against a live vulnerable target.

Run it against a host you own or are authorised to test:

bash

nuclei -u https://your-host -t CVE-2023-34192.yaml

Show the template (50 lines)

yaml

id: CVE-2023-34192

info:
  name: "Zimbra ZCS V - Cross-Site Scripting"
  author: vedas-arpsyndicate
  severity: critical
  description: |
    Cross Site Scripting vulnerability in Zimbra ZCS v.8.8.15 allows a remote authenticated attacker to execute
    arbitrary code via a crafted script to the /h/autoSaveDraft function.
  reference:
    - https://www.exploit.observer/?keyword=CVE-2023-34192&match=exact
    - https://subdomain.center/?engine=ammonites&keyword=zimbra&match=exact
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
    cvss-score: 9
    cve-id: CVE-2023-34192
    cwe-id: CWE-79
  metadata:
    verified: false
  tags: cve,cve2023,zimbra,xss,authenticated,kev,vkev,vuln
http:
  - raw:
      - |
        POST /zimbra/ HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded

        loginOp=login&username={{username}}&password={{password}}&client=preferred
      - |
        GET /h/autoSaveDraft?draftid=aaaaaaaaaaa%22%3E%3Cscript%3Ealert%28auocfvd5%29%3C%2Fscript%3E%3Cbbbbbbbb HTTP/1.1
        Host: {{Hostname}}

    matchers-condition: and
    matchers:
      - type: word
        part: body_2
        words:
          - "<script>alert(auocfvd5)</script>"
          - "zimbra"
        condition: and

      - type: word
        part: header_2
        words:
          - text/html

      - type: status
        part: header_2
        status:
          - 200

CVE-2023-34192.yaml on GitHub

Suricata rules (network detection)

1 rule that alert on traffic matching this exploit: VEDAS CVE-2023-34192 Zimbra ZCS V - Cross-Site Scripting. Add them to your Suricata rule set and reload.

Show the rules

suricata

alert http $EXTERNAL_NET any -> $HTTP_SERVERS $HTTP_PORTS (msg:"VEDAS CVE-2023-34192 Zimbra ZCS V - Cross-Site Scripting"; flow:established,to_server; http.uri; content:"autoSaveDraft"; nocase; content:"<script"; nocase; fast_pattern; classtype:web-application-attack; reference:cve,CVE-2023-34192; reference:url,https://www.exploit.observer/?keyword=CVE-2023-34192&match=exact; reference:url,https://subdomain.center/?engine=ammonites&keyword=zimbra&match=exact; sid:1009707; rev:1;)

CVE-2023-34192.rules on GitHub

References

Government sources

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-34192 (government-resource)

Other references

Other databases

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, CISA KEV, cve-scores (EPSS and VEDAS), Exploit Observer, vedas-signatures. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.