GitHub Advisoryadvisory · RubyGems

GHSA-wgx6-g857-jjf7 OpenC3 COSMOS: Hijacked session token can be used to reset password for persistence

HIGH Published 2026-04-22 Modified 2026-05-29 Official page ↗
Aliases
CVE-2026-42084
Ecosystem
RubyGems
Packages
openc3
Severity
High
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Weaknesses
CWE-620
Reviewed
2026-04-22

Affected packages

• RubyGems openc3: < 6.10.5 → fixed in 6.10.5 • RubyGems openc3: >= 7.0.0.pre.rc1, < 7.0.0-rc3 → fixed in 7.0.0-rc3

Description

Summary The OpenC3 password change functionality allows a user to change their password without providing the old password, by accepting a valid session token instead. In assumed breach scenarios, this behaviour can be exploited by an attacker who has already obtained a valid session token, to gain persistence in hijacked account (including admin) and prevent legitimate users from accessing the account. Details The design flaw in authentication model (authentication.rb) allows for interchangeable use of password and session tokens for user authentication As old tokens are not revoked upon password reset, an attacker who has obtained a valid session token can continue to authenticate and change the account’s password even after the victim resets it, thereby maintaining persistent control over the compromised account. PoC 1. Attacker is logged in user account with hijacked valid session token, but not knowing the actual password 2. Legitimate user, as preventive action, changes his password (_password123_) using old password (_password_), that he knows, then establishes new session 3. Attacker issues another password change request (in web proxy like Burp) supplying his still valid token as _old_password_, changing it to attacker-password, from this point preventing any other legitimate users from accessing account Impact Persistence of an attacker who obtained valid session token and preventing legitimate users from account access

Related

Alias · CVE (1)

  • CVE-2026-42084 OpenC3 COSMOS provides the functionality needed to send commands to and receive data from one or more embedded systems. vulnerability

Weakness · CWE (1)

  • CWE-620 Unverified Password Change weakness

References