Token theft via unvalidated baseUrl parameter
Published Mar 4, 2026 · Updated Mar 4, 2026
URL parameter injection in LangSmith Studio before 0.12.71 allows remote attackers to steal bearer tokens through malicious links. LangSmith Studio accepts a baseUrl parameter without restricting it to user-defined allowed origins, then sends the bearer token, user ID, and workspace ID to the attacker-controlled server. An authenticated user must click the crafted link; the stolen token remains valid for five minutes and grants the attacker the victim's workspace permissions.
Summary
What happened
URL parameter injection in LangSmith Studio before 0.12.71 allows remote attackers to steal bearer tokens through malicious links. LangSmith Studio accepts a baseUrl parameter without restricting it to user-defined allowed origins, then sends the bearer token, user ID, and workspace ID to the attacker-controlled server. An authenticated user must click the crafted link; the stolen token remains valid for five minutes and grants the attacker the victim's workspace permissions.
The record
- CVE
- CVE-2026-25750
- Published
- Mar 4, 2026
- Updated
- Mar 4, 2026
- Vendor
- LangChain
- Product
- LangSmith Studio
- Classifications
- CWE-74, T1528, T1204.001
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 4, 2026CVE publishedPublication date reported by the CVE source.
- Mar 4, 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?
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- Affected versionversion=< 0.12.71
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What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
Public exploit references
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Technologies
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Your stack
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