CVE-2026-89011 HIGH

CVE-2026-89011: isomorphic-git < 1.42.0 Prototype Pollution via getRemoteInfo

Vendor Isomorphic-Git
Product isomorphic-git
Weakness CWE-1321
Published September 10, 2026
Last update September 10, 2026

CVSS base score

7.1/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction —
Confidentiality —
Integrity —

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N

What the vulnerability does

01Description

isomorphic-git before 1.42.0 contains a prototype pollution vulnerability in the getRemoteInfo function that allows a malicious Git server operator to pollute Object.prototype by advertising crafted ref names containing '__proto__' path segments during ref negotiation. Attackers controlling a Git server can advertise a specially crafted ref such as '__proto__/corsProxy' to reroute all subsequent network operations through an attacker-controlled proxy, causing isomorphic-git to invoke the victim's onAuth callback and transmit credentials to the attacker when the victim calls getRemoteInfo with an attacker-supplied URL.

Key dates

02Disclosure timeline

September 10, 2026 CVE published