{"id":"CVE-2026-55244","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-55244","generatedAt":"2026-10-28T00:18:42.770Z","title":"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…","description":"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.","published":"2026-09-14T20:16:48.000Z","lastModified":"2026-09-30T17:51:56.000Z","status":"Deferred","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H"},"cwe":["CWE-248"],"affected":[],"epss":{"score":0.00177,"percentile":0.07236,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.18%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://github.com/lmfit/asteval/commit/9c625b3674f8d05f206708bb85afca17a87694a4","source":"security-advisories@github.com"},{"url":"https://github.com/lmfit/asteval/commit/c49c99a67acb63eb7410231932250bd820380e45","source":"security-advisories@github.com"},{"url":"https://github.com/lmfit/asteval/pull/153","source":"security-advisories@github.com"},{"url":"https://github.com/lmfit/asteval/releases/tag/1.0.9","source":"security-advisories@github.com"},{"url":"https://github.com/lmfit/asteval/security/advisories/GHSA-89v8-rhwq-hf77","source":"security-advisories@github.com"},{"url":"https://github.com/lmfit/asteval/security/advisories/GHSA-89v8-rhwq-hf77","source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-55244","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}