# CVE-2026-109294: Open WebUI memory exhaustion via compressed remote image

Source: https://junglewise.ai/threats/cve-2026-109294-open-webui-from-0-6-42-before-0-11-4-contains-an-uncontrolled  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-12. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-109294 · Severity: medium · CVSS 6.5 · Published 2026-10-12

Open WebUI is a web interface for interacting with language models. An authenticated user can cause a denial of service affecting all users by uploading a chat message containing a compressed image URL that the server decompresses without size limits, consuming gigabytes of memory in seconds.

Technologies: [Open WebUI](https://junglewise.ai/threats/technologies/open-webui-open-webui). Vendors: [Open WebUI](https://junglewise.ai/threats/vendors/open-webui).

## Quick answers

**Is CVE-2026-109294 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-109294 being exploited in the wild.

**How severe is CVE-2026-109294?** Medium severity, with a CVSS score of 6.5, published 12 October 2026.

**Which products and versions are affected?** Open WebUI 0.6.42 before 0.11.4.

**Is there a fix for CVE-2026-109294?** Yes: fixed in 0.11.4. Until then: Restrict network access to Open WebUI or limit which users can send chat messages until an upgrade to 0.11.4 is deployed. The fix reads responses incrementally, disables automatic decompression, and rejects any compressed response before inlining. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-109294 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-109294?** Check whether you run Open WebUI at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 0.11.4

Restrict network access to Open WebUI or limit which users can send chat messages until an upgrade to 0.11.4 is deployed. The fix reads responses incrementally, disables automatic decompression, and rejects any compressed response before inlining.

## Technical details

The get_image_base64_from_url function in Open WebUI reads HTTP response bodies entirely into memory before encoding them, with no size limits. An attacker-controlled server can send gzip-encoded content that decompresses to gigabytes in the server process; HTTP transparent decompression applies before any checks. The vulnerability exists in both synchronous (pre-0.9.0) and asynchronous implementations, and requests can be repeated unbounded.

## Affected products

- Open WebUI Open WebUI 0.6.42 before 0.11.4

## Timeline

- 2026-09-27: disclosed
- 2026-10-12: patched

## References

- [https://github.com/open-webui/open-webui/security/advisories/GHSA-w8j8-jv6j-3m47](https://github.com/open-webui/open-webui/security/advisories/GHSA-w8j8-jv6j-3m47)
- [https://www.vulncheck.com/advisories/open-webui-0.6.42-before-0.11.4-memory-exhaustion-via-compressed-remote-image](https://www.vulncheck.com/advisories/open-webui-0.6.42-before-0.11.4-memory-exhaustion-via-compressed-remote-image)

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- [Open WebUI denial of service in recurrence rule validation](https://junglewise.ai/threats/cve-2026-109299-open-webui-from-0-9-0-before-0-11-4-contains-a-denial-of-service)
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