CVE-2026-13435
PythonREPL sandbox escape in IBM Langflow allows arbitrary code execution.
Is CVE-2026-13435 being exploited?
Not confirmed. CVE-2026-13435 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.29% probability of exploitation in the next 30 days.
How severe is CVE-2026-13435?
CVE-2026-13435 is rated Critical with a CVSS score of 9.9. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-13435?
Yes. A fix has been recorded for CVE-2026-13435. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-13435 affect?
CVE-2026-13435 affects IBM Langflow OSS 1.0.0 - 1.10.1, Langflow PythonREPL sandbox, Langflow instances with exposed UI/API. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-13435?
Isolate Langflow, disable PythonREPL, restrict access, monitor, apply vendor patch when released.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Sandbox bypass leads to arbitrary code execution on host; attacker can run commands, access files, and pivot to networks.
Immediate action required
- affected>= 1.0.0 and <= 1.10.1
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.