CVE-2026-70489: Open WebUI: Instance-wide stall via automation recurrence rules that force multi-second parsing

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-08-04 · updated 2026-09-18
Weakness: CWE-400

Description

Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.9.0 until 0.11.0, automation recurrence parsing in backend/open_webui/utils/automations.py anchored minutely and hourly rules at a fixed date of 2000-01-01 and then walked forward one interval at a time to find the next run. A single FREQ=MINUTELY rule enumerates roughly a quarter-century of occurrences synchronously on the event loop that also serves scheduler, HTTP, and WebSocket traffic, and the scheduler recomputes the next run for every claimed row on each poll. This causes availability impact for every other user of the instance. This issue is fixed in 0.11.0.

Affected products

open-webui: from 0.9.0 before 0.11.0 — fixed in 0.11.0

How to fix

Upgrade to a fixed version: open-webui 0.11.0. Check the vendor advisory for mitigations.

References

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