CVE-2026-49375Network attack vector

Browser script execution via repository page reflection

Published May 29, 2026 · Updated May 29, 2026

Reflected XSS in JetBrains TeamCity On-Premises before 2026.1 and before 2025.11.5 allows remote attackers to run script in a user browser. The repository download page reflects attacker-controlled input into its HTML response without adequate output neutralization; JetBrains has not disclosed the parameter or rendering sink. Exploitation requires a user to open a crafted repository download request; injected script then runs in that user’s TeamCity browser context.

CVSS severity6.1
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in JetBrains TeamCity On-Premises before 2026.1 and before 2025.11.5 allows remote attackers to run script in a user browser. The repository download page reflects attacker-controlled input into its HTML response without adequate output neutralization; JetBrains has not disclosed the parameter or rendering sink. Exploitation requires a user to open a crafted repository download request; injected script then runs in that user’s TeamCity browser context.

The record

CVE
CVE-2026-49375
Published
May 29, 2026
Updated
May 29, 2026
Vendor
JetBrains
Product
TeamCity On-Premises
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 29, 2026CVE publishedPublication date reported by the CVE source.
  2. May 29, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <2026.1, 2025.11.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

JetBrains · TeamCity On-Premisesversion=0 <2026.1, 2025.11.5

Published CVSS scores

6.1JetBrains s.r.o.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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