{"id":"UBUNTU-CVE-2026-31221","details":"PyTorch-Lightning versions 2.6.0 and earlier contain an insecure deserialization vulnerability (CWE-502) in the checkpoint loading mechanism. The LightningModule.load_from_checkpoint() method, which is commonly used to load saved model states, internally calls torch.load() without setting the security-restrictive weights_only=True parameter. This default behavior allows the deserialization of arbitrary Python objects via the Pickle module. A remote attacker can exploit this by providing a maliciously crafted checkpoint file, leading to arbitrary code execution on the victim's system when the file is loaded.","modified":"2026-05-20T22:02:56.543481839Z","published":"2026-05-12T16:16:00Z","upstream":["CVE-2026-31221"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-31221"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-31221"}],"affected":[{"package":{"name":"pytorch","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/pytorch?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.7.1-7","1.8.1-4"],"ecosystem_specific":{"binaries":[{"binary_name":"libtorch-test","binary_version":"1.8.1-4"},{"binary_name":"libtorch1.8","binary_version":"1.8.1-4"},{"binary_version":"1.8.1-4","binary_name":"python3-torch"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-31221.json"}},{"package":{"name":"pytorch","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/pytorch?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.6.0+dfsg-5build1","2.6.0+dfsg-7"],"ecosystem_specific":{"binaries":[{"binary_name":"libtorch-test","binary_version":"2.6.0+dfsg-7"},{"binary_version":"2.6.0+dfsg-7","binary_name":"libtorch2.6"},{"binary_name":"python3-torch","binary_version":"2.6.0+dfsg-7"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-31221.json"}},{"package":{"name":"pytorch","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/pytorch?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.6.0+dfsg-7","2.6.0+dfsg-9","2.9.1+dfsg-1~exp1ubuntu2"],"ecosystem_specific":{"binaries":[{"binary_name":"libtorch-test","binary_version":"2.9.1+dfsg-1~exp1ubuntu2"},{"binary_name":"libtorch2.9","binary_version":"2.9.1+dfsg-1~exp1ubuntu2"},{"binary_name":"python3-torch","binary_version":"2.9.1+dfsg-1~exp1ubuntu2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-31221.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"},{"type":"Ubuntu","score":"medium"}]}