Vulnerability · Published Jun 24, 2026 · Assigned by zdi

CVE-2026-10043MosaicML Composer Deserialization of Untrusted Data Remote Code Execution Vulnerability

High 7.8

In plain English

A high-severity unsafe deserialization in Composer from MosaicML. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 46% of all known vulnerabilities).

Severity (CVSS 3.0)7.8High

Exploit odds (30 days)0.5%top 54.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

MosaicML Composer Deserialization of Untrusted Data Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of MosaicML Composer. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the parsing of checkpoints. The issue results from the lack of proper validation of user-supplied data, which can result in deserialization of untrusted data. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-27990.

Affected products (as reported)

Vendor	Product	Versions
MosaicML	Composer	0.32.1

Weakness: CWE-502 · Vector: CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

References

ZDI-26-384 x_research-advisory
vendor-provided URL vendor-advisory