Xorbits Xoscar through version 0.11.2 has a critical deserialization flaw (CVE-2026-49950) that needs no authentication. Remote attackers can use it to run arbitrary code by sending crafted data over the actor-pool TCP channel.
What Is It
CVE-2026-49950 is an insecure deserialization vulnerability (CWE-502) in Xoscar, the actor framework from Xorbits. The NVD record says SocketChannel.recv() takes unvalidated data from the actor-pool TCP channel and passes it straight to cloudpickle.loads(). Deserialization happens before the message type is checked, so a crafted payload can trigger pickle __reduce__ gadget execution. The attacker's code then runs in the context of the server process.
VulnCheck disclosed the issue. Its references point to the affected code at the v0.11.2 tag: python/xoscar/backends/communication/socket.py (lines 99–104) and python/xoscar/serialization/core.pyx (line 260).
Why It Matters
The vulnerability has a CVSS v3.1 base score of 9.8 (CRITICAL), with vector AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Its CVSS v4.0 score is 9.3 (CRITICAL). An attacker can exploit it over the network with low complexity, and needs no authentication or user interaction.
The NVD description says the Xoscar server process often runs as root on GPU nodes. In that case, a successful attack could give the attacker full control of high-value compute infrastructure.
As of this writing, CVE-2026-49950 is not listed in the CISA Known Exploited Vulnerabilities (KEV) Catalog. This means KEV does not currently confirm active exploitation in the wild.
What's Vulnerable
- Vendor: xorbitsai
- Product: xoscar
- Affected versions: 0.1.0 through 0.11.2 (inclusive, semver)
- Repository: https://github.com/xorbitsai/xoscar
Any deployment that exposes the Xoscar actor-pool TCP channel to untrusted networks is at risk.
Patch Status
The NVD record lists no fixed version. Because the CVE is not in the CISA KEV Catalog, there is no CISA KEV required action or due date for it. The NVD status is "Received," which means NVD has not finished its analysis. Administrators should check the Xoscar repository and the VulnCheck advisory for remediation guidance and new releases. Until a fix is confirmed, treat every version up to and including 0.11.2 as vulnerable.