CVE-2026-13482 Overview
CVE-2026-13482 affects skypilot-org/skypilot up to version 0.12.0. The flaw resides in the username.encode function within sky/users/server.py, part of the User ID Handler component. The implementation relies on a weak hash algorithm [CWE-327] to derive user identifiers, allowing remote attackers to predict or collide hashed values under specific conditions.
The attack requires high complexity and difficult exploitation, limiting practical impact. However, a public exploit exists, and the vendor was notified prior to disclosure. The vulnerability affects the integrity of user identifier processing rather than confidentiality or availability.
Critical Impact
Predictable user identifier generation in SkyPilot may enable identity collision or spoofing scenarios in multi-tenant deployments.
Affected Products
- SkyPilot versions up to and including 0.12.0
- sky/users/server.py User ID Handler component
- Deployments exposing the SkyPilot API server over a network
Discovery Timeline
- 2026-06-28 - CVE-2026-13482 published to NVD
- 2026-06-29 - Last updated in NVD database
Technical Details for CVE-2026-13482
Vulnerability Analysis
The vulnerability is a Weak Hash Algorithm issue [CWE-327] in SkyPilot's user identity subsystem. The username.encode function in sky/users/server.py uses a cryptographically weak hashing primitive to derive user identifiers from username input. Weak hash functions produce outputs vulnerable to collision, preimage, and prediction attacks that stronger algorithms such as SHA-256 resist.
Because the hash output is used within the User ID Handler, attackers with knowledge of the algorithm and input space can attempt to generate identifiers that collide with legitimate user IDs. The attack vector is network-based and does not require authentication, but exploitation is rated as high complexity.
Root Cause
The root cause is the selection of a cryptographically weak hash function inside username.encode. Identity-linked values must use collision-resistant algorithms. Weak hashes were retained in SkyPilot up to 0.12.0, exposing the identifier generation logic to precomputation and collision techniques.
Attack Vector
A remote unauthenticated attacker interacts with the SkyPilot API server that consumes user identifier data. By supplying crafted usernames or precomputed inputs, the attacker attempts to produce hash outputs that align with existing user identifiers. Successful collisions may allow limited integrity impact against user handling logic. Refer to the GitHub Issue Discussion and the VulDB Vulnerability Details for the disclosure specifics.
No verified exploit code is published in a form suitable for reproduction here. See the GitHub Project Repository for source-level review of the affected function.
Detection Methods for CVE-2026-13482
Indicators of Compromise
- Unusual creation of user accounts with atypical or algorithmically generated username patterns targeting the SkyPilot API
- Repeated requests to user-related endpoints in sky/users/server.py from a single remote source
- Log entries showing user identifier collisions or conflicts within SkyPilot audit output
Detection Strategies
- Review the SkyPilot codebase for calls to username.encode and confirm the hashing primitive in use against the fixed version
- Correlate API access logs with authentication events to spot identifier-mapping anomalies
- Inspect network traffic to the SkyPilot API server for high-volume enumeration of user endpoints
Monitoring Recommendations
- Enable verbose audit logging on the SkyPilot API server and forward logs to a centralized analytics platform
- Alert on multiple failed or unusual user-lookup requests within short time windows
- Track version metadata of deployed SkyPilot instances to detect unpatched hosts
How to Mitigate CVE-2026-13482
Immediate Actions Required
- Inventory all SkyPilot deployments and identify instances running 0.12.0 or earlier
- Restrict network exposure of the SkyPilot API server to trusted management networks only
- Enforce strong authentication in front of the SkyPilot API where the platform is accessible externally
- Monitor the GitHub Issue Discussion for the official fix release
Patch Information
Upgrade SkyPilot to a release later than 0.12.0 once the maintainers publish a fixed version replacing the weak hash in username.encode with a collision-resistant algorithm. Track patch availability through the GitHub Project Repository and the VulDB CVE Listing.
Workarounds
- Place the SkyPilot API server behind an authenticated reverse proxy that filters unauthenticated user-lookup traffic
- Restrict username inputs to a controlled allowlist to reduce the attacker-controlled input space
- Segment SkyPilot control-plane traffic on a dedicated network with strict ingress filtering
# Example: restrict SkyPilot API access at the network level
iptables -A INPUT -p tcp --dport 46580 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 46580 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
