CVE-2025-52876VulnerabilityPublished 23 Jun 2025

CVE-2025-52876: JetBrains TeamCity · Cross-site Scripting

Affects JetBrains TeamCitySource CVE Database V5

Not known to be exploited · 37% EPSS · CVSS 5.4 Medium.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

5.4Medium

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

EPSS: 37.8% chance of exploitation in 30 days – higher than 98% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: Required
Scope: Changed
Confidentiality: Low
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: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
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: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to 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 23 Jun 2025
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 2026-10-25.

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 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
JetBrains TeamCity	Affected =0	Fixed in–

AI-suggested

1. Immediate upgrade to JetBrains TeamCity version 2025.03.3 or later once available, as this will contain the official fix for the reflected XSS vulnerability. 2. In the interim, restrict access to the TeamCity web interface to trusted networks and users only, minimizing exposure to untrusted actors. 3. Implement strict Content Security Policy (CSP) headers on the TeamCity server to limit the execution of injected scripts and reduce the impact of XSS attacks. 4. Educate users with access to TeamCity about the risks of clicking on suspicious links, especially those that could target the favoriteIcon page. 5. Monitor web server logs for unusual requests targeting the favoriteIcon page or containing suspicious query parameters indicative of XSS attempts. 6. Employ Web Application Firewalls (WAF) with rules tuned to detect and block reflected XSS payloads targeting TeamCity endpoints. 7. Review and enforce the principle of least privilege for TeamCity users to reduce the potential impact of compromised accounts. 8. Conduct internal penetration testing and code reviews focusing on input validation and output encoding practices within TeamCity customizations or plugins.

Description

In JetBrains TeamCity before 2025.03.3 reflected XSS on the favoriteIcon page was possible

Impact

For European organizations, the impact of this vulnerability can be significant, especially for enterprises relying on TeamCity for continuous integration and deployment workflows. Successful exploitation could lead to partial compromise of user accounts with limited privileges, enabling attackers to steal session cookies or perform actions within the scope of the compromised user. This could result in unauthorized access to build configurations, exposure of sensitive build metadata, or injection of malicious code into build pipelines if further chained with other vulnerabilities or misconfigurations. While the direct impact on availability is none, the integrity and confidentiality risks could undermine trust in software delivery processes. Organizations in sectors with stringent compliance requirements (e.g., finance, healthcare, critical infrastructure) may face regulatory repercussions if sensitive data is exposed or manipulated. Additionally, the requirement for user interaction and privileges somewhat limits the attack surface but does not eliminate risk, especially in environments where many users have access to TeamCity. The reflected XSS could also be used as a foothold for social engineering attacks targeting developers or DevOps personnel, potentially leading to broader compromise.

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

jetbrains.com/privacy-security/issues-fixed/ (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 23 Jun 2025, 14:29 UTC

WeaknessesCWE-79

Technical details

References

Community reviews

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