CVE-2026-13482: SkyPilot User ID Hash Weakness

Technical summary

CVE-2026-13482 is a weak cryptographic hash vulnerability in SkyPilot versions up to 0.12.0. The flaw exists in the username.encode function within sky/users/server.py, part of the User ID Handler component. An attacker can exploit this by leveraging the predictable or reversible nature of the hash to potentially forge or manipulate user identity tokens. The vulnerability is classified under CWE-327 (Use of a Broken or Risky Cryptographic Algorithm) and CWE-328 (Use of Insufficiently Random Values). Exploitation requires high complexity and is difficult to execute, but exploit code is now publicly available.

Business impact

The integrity risk is contained: an attacker could potentially forge or tamper with user identity information in SkyPilot deployments. This could allow unauthorized access to infrastructure resources or unauthorized operations within a cluster. For organizations using SkyPilot in production environments with sensitive workloads or multi-tenant setups, this represents a credential/identity manipulation risk rather than a widespread compromise vector. The low CVSS score reflects the difficulty of exploitation and limited scope of impact, but the practical concern depends on how SkyPilot is deployed and whether user isolation is critical to your security posture.

Affected systems

SkyPilot versions up to and including 0.12.0 are affected. The vulnerability is in the open-source SkyPilot project maintained by skypilot-org. If your organization uses SkyPilot for cloud resource orchestration or workload scheduling, verify your installed version against the 0.12.0 threshold. Affected deployments are those where the User ID Handler is active and user authentication or identity isolation is relied upon for access control.

Exploitability

Exploitation is difficult and requires high complexity, evidenced by a CVSS Attack Complexity (AC) rating of High. However, exploit details are now public, lowering the barrier for determined attackers. No CVSS user interaction is required, and the attack is network-accessible, meaning a remote attacker can attempt exploitation without physical access. The practical difficulty remains non-trivial, but teams should not assume obscurity as a defense given public proof-of-concept availability.

Remediation

Upgrade SkyPilot to a patched version released after 0.12.0. Verify the exact patched version against the official SkyPilot GitHub repository or vendor advisory. If immediate upgrade is not feasible, implement network-level access controls to restrict direct connectivity to affected SkyPilot clusters and monitor for suspicious user identity token manipulation or forged authentication attempts.

Patch guidance

Visit the SkyPilot GitHub repository (github.com/skypilot-org/skypilot) and check the releases page for versions newer than 0.12.0. The vendor was contacted early during the disclosure process, so a patch should be available or imminent. Review the release notes to confirm that the User ID Handler hashing has been strengthened to use a cryptographically sound algorithm (e.g., bcrypt, PBKDF2, or Argon2 if applicable to SkyPilot's architecture). Test the patched version in a staging environment before deployment to production.

Detection guidance

Monitor SkyPilot server logs in sky/users/server.py for anomalous user ID encoding behavior or failed authentication attempts. If you have HTTP/API traffic logging, look for repeated attempts to forge or manipulate user tokens. Check for any unusual privilege escalations or resource access patterns that coincide with the public exploit disclosure date (on or after 2026-06-28). Implement host-based intrusion detection rules that flag attempts to read or tamper with SkyPilot's user identity files or token storage.

Why prioritize this

Although the CVSS score is low (3.7), this vulnerability warrants timely attention because: (1) exploit code is publicly available, reducing the technical barrier to attack; (2) it affects user identity integrity, a foundational security control; (3) SkyPilot is increasingly used in cloud infrastructure automation pipelines where compromised identity could lead to lateral movement or resource hijacking. Prioritize this as a medium-effort, medium-urgency patch cycle item—not an emergency, but not a defer-to-next-quarter ticket either.

Risk score, explained

The CVSS 3.1 score of 3.7 (LOW) reflects: Network accessibility (AV:N), high attack complexity (AC:H), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), no confidentiality impact (C:N), low integrity impact (I:L), and no availability impact (A:N). The low severity is justified by the difficulty of exploitation and limited blast radius (only user identity, not system-wide compromise). However, the public exploit availability and foundational nature of user identity systems mean the practical risk may be higher than the numeric score suggests for organizations where SkyPilot is critical infrastructure.

Frequently asked questions