VulnerabilityPublished 2 Jan 2024Updated 3 Jun 2025

CVE-2017-20188: Zimbra zm-ajax · Cross-site Scripting

Affects Zimbra zm-ajaxSource CVE Database V5

Not known to be exploited · CVSS 2.6 Low.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 3.1 base score

2.6Low

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 33% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N

Attack Vector: Network
Attack Complexity: High
Privileges Required: Low
User Interaction: Required
Scope: Unchanged
Confidentiality: None
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 2 Jan 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
GitHubzimbra/zm-ajax`pkg:github/zimbra/zm-ajax`Other threats	Affected =8.8.0 =8.8.1	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Immediate upgrade of Zimbra Collaboration Suite to version 8.8.2 or later, which contains the official patch addressing CVE-2017-20188.
Implement strict Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of potential XSS attacks.
Conduct thorough input validation and output encoding on all user-supplied data within custom Zimbra extensions or integrations to prevent injection of malicious content.
Employ web application firewalls (WAFs) with rules tailored to detect and block XSS payloads targeting Zimbra interfaces.
Educate users about the risks of interacting with suspicious links or messages that could trigger XSS exploitation, emphasizing cautious behavior in email and collaboration platforms.
Regularly audit and monitor Zimbra logs for unusual activities or error messages related to XFormItem.setError function calls that might indicate attempted exploitation.
For organizations unable to upgrade immediately, consider isolating the affected Zimbra services behind additional security layers or restricting access to trusted networks to reduce exposure.

Description

A vulnerability has been found in Zimbra zm-ajax up to 8.8.1 and classified as problematic. Affected by this vulnerability is the function XFormItem.prototype.setError of the file WebRoot/js/ajax/dwt/xforms/XFormItem.js. The manipulation of the argument message leads to cross site scripting. The attack can be launched remotely. The complexity of an attack is rather high. The exploitation appears to be difficult. Upgrading to version 8.8.2 is able to address this issue. The identifier of the patch is 8d039d6efe80780adc40c6f670c06d21de272105. It is recommended to upgrade the affected component. The identifier VDB-249421 was assigned to this vulnerability.

Impact

For European organizations using Zimbra Collaboration Suite versions 8.8.0 or 8.8.1, this vulnerability poses a limited risk primarily related to the integrity of web content displayed to users. Successful exploitation could allow attackers to execute malicious scripts in users' browsers, potentially leading to session hijacking, phishing, or defacement within the affected web application context. However, due to the high complexity and requirement for user interaction, the likelihood of widespread exploitation is low. Organizations handling sensitive communications or operating in regulated sectors (e.g., finance, healthcare, government) should be cautious, as even limited script injection could facilitate targeted social engineering or lateral attacks. The vulnerability does not compromise confidentiality or availability directly, so critical data leakage or service disruption risks are minimal. Nonetheless, the presence of XSS vulnerabilities can undermine user trust and may be leveraged as part of multi-stage attacks. European entities with significant user bases relying on Zimbra for email and collaboration services should prioritize patching to maintain security posture and compliance with data protection regulations such as GDPR.

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #1OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Implementation · Architecture and Design
Understand the context in which your data will be used and the encoding that will be expected. This is especially important when transmitting data between different components, or when generating outputs that can contain multiple encodings at the same time, such as web pages or multi-part mail messages.
Architecture and Design · Implementation · Attack Surface Reduction
Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide…
OWASP Cheat Sheets
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Injection Prevention (opens in a new tab)
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
OWASP ASVS 4.0.3
V5.3.3 (opens in a new tab)
V1.5.1 (opens in a new tab)
Attack patterns
XSS Using MIME Type Mismatch (opens in a new tab)
DOM-Based XSS (opens in a new tab)
Reflected XSS (opens in a new tab)
Stored XSS (opens in a new tab)
Cross-Site Scripting (XSS) (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Jul 2025, 07:28 UTC

WeaknessesCWE-79

Technical details

References

Community reviews

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