CVE-2026-8859
Path traversal in IBM Langflow allows arbitrary file writes via crafted Content-Disposition filenames.
Is CVE-2026-8859 being exploited?
Not confirmed. CVE-2026-8859 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 0.56% probability of exploitation in the next 30 days.
How severe is CVE-2026-8859?
CVE-2026-8859 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-2026-8859?
Yes. A fix has been recorded for CVE-2026-8859. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-8859 affect?
CVE-2026-8859 affects IBM Langflow OSS 1.0.0 through 1.10.0, APIRequest component 'Save to File' feature. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-8859?
Disable Save to File, block untrusted HTTP sources, apply vendor patch when released.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Attacker controlling an external HTTP server can craft filenames with ../ to cause arbitrary file writes as the Langflow process, enabling data overwrite, code injection, or persistence.
Immediate action required
- affected>= 1.0.0 and <= 1.10.0
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.