{"id":"UBUNTU-CVE-2026-55244","details":"ASTEVAL is an evaluator of Python expressions and statements. Prior to 1.0.9, FROM_PY in asteval/astutils.py exposes BaseException, SystemExit, KeyboardInterrupt, and GeneratorExit to expressions evaluated by asteval.Interpreter.eval(), while run() and eval() in asteval/asteval.py catch Exception rather than these non-Exception BaseException subclasses. When an attacker-controlled expression raises one of these classes, on_raise() passes the class to raise_exception(), and the resulting exception bypasses the interpreter's safety handlers and propagates into the calling application. A consuming service that evaluates untrusted expressions can therefore be terminated or have signal and cleanup handling disrupted, causing denial of service. The separately documented read-only open() capability is not part of this vulnerability. This issue is fixed in version 1.0.9.","modified":"2026-09-24T02:00:33.549976613Z","published":"2026-09-14T20:16:00Z","upstream":["CVE-2026-55244"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-55244"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-55244"},{"type":"REPORT","url":"https://github.com/lmfit/asteval/security/advisories/GHSA-89v8-rhwq-hf77"},{"type":"REPORT","url":"https://github.com/lmfit/asteval/pull/153"}],"affected":[{"package":{"name":"python-asteval","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/python-asteval?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.9.12-1","0.9.12-2","0.9.17-1"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-asteval","binary_version":"0.9.17-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55244.json"}},{"package":{"name":"python-asteval","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/python-asteval?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.9.19-2","0.9.25-2"],"ecosystem_specific":{"binaries":[{"binary_version":"0.9.25-2","binary_name":"python3-asteval"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55244.json"}},{"package":{"name":"python-asteval","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/python-asteval?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.9.30-1","0.9.31-1"],"ecosystem_specific":{"binaries":[{"binary_version":"0.9.31-1","binary_name":"python3-asteval"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55244.json"}},{"package":{"name":"python-asteval","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/python-asteval?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.0.6-2"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-asteval","binary_version":"1.0.6-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55244.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]}