CVE-2026-54015

Open WebUI Prompt history IDOR: unbound history_id allows cross-prompt read and deletion

Security boundary crossed: prompt confidentiality and integrity.

Prompt history snapshots can contain private prompt text, internal instructions, and sensitive variables. With a known victim prompt_history.id, an attacker can read another user's snapshot (via the diff endpoint or by restoring it into their own prompt) and delete another user's history entry. The active prompt row is not destroyed; the delete impact is against version history. Exploitation requires knowing or obtaining victim history UUIDs, so severity depends on adjacent ID exposure.

CVE-2026-54015 has a CVSS score of 6.4 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.9.6); upgrading removes the vulnerable code path.

Kodem intelligence

Bind every prompt-history operation to the authorized prompt before acting on a history ID, mirroring the single-entry read endpoint:

• compute_diff() should accept prompt_id and query both entries with PromptHistory.prompt_id == prompt_id alongside the id filter.
• delete_history_entry() should accept prompt_id and filter filter_by(id=history_id, prompt_id=prompt_id).
• update_prompt_version() should reject history_entry.prompt_id != prompt_id before restoring.

Return 404/403 on mismatch.

1. What is CVE-2026-54015? CVE-2026-54015 is a medium-severity security vulnerability in open-webui (pip), affecting versions <= 0.9.5. It is fixed in 0.9.6.
2. How severe is CVE-2026-54015? CVE-2026-54015 has a CVSS score of 6.4 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of open-webui are affected by CVE-2026-54015? open-webui (pip) versions <= 0.9.5 is affected.
4. Is there a fix for CVE-2026-54015? Yes. CVE-2026-54015 is fixed in 0.9.6. Upgrade to this version or later.
5. Is CVE-2026-54015 exploitable, and should I be worried? Whether CVE-2026-54015 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-54015 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-54015? Upgrade open-webui to 0.9.6 or later.