Credential theft via unvalidated Git ref traversal
Published Sep 10, 2026 · Updated Sep 10, 2026
Prototype pollution in isomorphic-git before 1.42.0 allows remote attackers to expose credentials through a malicious Git server. getRemoteInfo splits server-advertised ref names and traverses a plain object without rejecting proto, so a crafted ref writes corsProxy to Object.prototype and reroutes later requests. Exploitation requires an application to query an attacker-supplied URL and later provide onAuth credentials in the same JavaScript realm.
Summary
What happened
Prototype pollution in isomorphic-git before 1.42.0 allows remote attackers to expose credentials through a malicious Git server. getRemoteInfo splits server-advertised ref names and traverses a plain object without rejecting proto, so a crafted ref writes corsProxy to Object.prototype and reroutes later requests. Exploitation requires an application to query an attacker-supplied URL and later provide onAuth credentials in the same JavaScript realm.
The record
- CVE
- CVE-2026-89011
- Published
- Sep 10, 2026
- Updated
- Sep 10, 2026
- Vendor
- isomorphic-git
- Product
- isomorphic-git
- Classifications
- CWE-1321, T1557
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 10, 2026CVE publishedPublication date reported by the CVE source.
- Sep 10, 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.
- Affected versionversion=0 <1.42.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
- Upstream malicious-ref proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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