CVE-2026-26193

HIGHPre-NVD 7.37.3—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.3 under the CNA's CVSS (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 90% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: cna:github_m, epss
7.3
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.3Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Open WebUI vulnerable to Stored XSS via iFrame embeds in response messages

Summary

Manually modifying chat history allows setting the embeds property on a response message, the content of which is loaded into an iFrame with a sandbox that has allow-scripts and allow-same-origin set, ignoring the "iframe Sandbox Allow Same Origin" configuration. This enables stored XSS on the affected chat. This also triggers when the chat is in the shared format. The result is a shareable link containing the payload that can be distributed to any other users on the instance.

Details

The flaw stems from how iFrames are constructed here: https://github.com/open-webui/open-webui/blob/6f1486ffd0cb288d0e21f41845361924e0d742b3/src/lib/components/chat/Messages/ResponseMessage.svelte#L689-L703

messages.embeds is a user controlled property and so can be arbitrarily set by the user to a payload of their choosing. Since allowScripts and allowSameOrigin are harcoded as true here the sandboxing offers essentially no protection.

PoC

Create an arbitrary chat:

Edit the model response:

Before saving, configure the browser to use an HTTP proxy tool (Burp/Caido/ZAP) and intercept the save request. Find the object within the history and then messages objects (not the messages array) that corresponds to the edited text.

On this object, add an embeds key and list value as shown below, forward the request and refresh the page.

This results in XSS via the controlled content getting rendered in the iFrame. Note the bold text is just to aid demonstration. console.log is used to prove JS execution because the lack of allow-modals on the iFrame sandbox prevents alerts.

The same payload triggers when the chat is shared.

Impact

Any user can create a weaponised chat that can be shared and subsequently used to target other users.

Low privilege users are at risk of having their session taken over by a payload that reads their token from local storage and exfiltrates it to an attacker controlled server.

Admins are at risk of exposing the server to RCE via same chain described in GHSA-w7xj-8fx7-wfch.

CVSS v3
7.3
EG Score
7.3(medium)
EPSS
9.8%
KEV
Not listed

Published

July 7, 2026

Last Modified

July 7, 2026

Vendor Advisories for CVE-2026-26193(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Data Freshness Timeline

(refreshed 24× in last 7d / 29× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-15 18:30 UTCEG score recompute
  2. 2026-07-15 16:57 UTCEPSS rescore
  3. 2026-07-15 16:57 UTCEPSS rescore
  4. 2026-07-15 05:31 UTCEG score recompute
  5. 2026-07-15 02:00 UTCEPSS rescore
  6. 2026-07-15 02:00 UTCEPSS rescore
  7. 2026-07-14 16:34 UTCEG score recompute
  8. 2026-07-14 03:42 UTCEG score recompute
  9. 2026-07-13 22:30 UTCEPSS rescore
  10. 2026-07-13 14:50 UTCEG score recompute
  11. 2026-07-13 06:13 UTCEPSS rescore
  12. 2026-07-13 06:13 UTCEPSS rescore
  13. 2026-07-13 01:58 UTCEG score recompute
  14. 2026-07-12 13:06 UTCEG score recompute
  15. 2026-07-12 05:46 UTCEPSS rescore
  16. 2026-07-12 05:46 UTCEPSS rescore
  17. 2026-07-12 00:14 UTCEG score recompute
  18. 2026-07-11 11:22 UTCEG score recompute
  19. 2026-07-11 08:27 UTCEPSS rescore
  20. 2026-07-10 22:30 UTCEG score recompute
  21. 2026-07-10 09:38 UTCEG score recompute
  22. 2026-07-09 20:45 UTCEG score recompute
  23. 2026-07-09 19:10 UTCEPSS rescore
  24. 2026-07-09 07:53 UTCEG score recompute
  25. 2026-07-08 19:01 UTCEG score recompute
Show 4 more
  1. 2026-07-08 15:15 UTCEPSS rescore
  2. 2026-07-08 15:15 UTCEPSS rescore
  3. 2026-07-08 06:06 UTCEG score recompute
  4. 2026-07-07 17:13 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-26193?
CVE-2026-26193 is a high vulnerability published on July 7, 2026. Open WebUI vulnerable to Stored XSS via iFrame embeds in response messages Summary Manually modifying chat history allows setting the embeds property on a response message, the content of which is loaded into an iFrame with a sandbox that has allow-scripts and allow-same-origin set, ignoring the…
When was CVE-2026-26193 disclosed?
CVE-2026-26193 was first published in the National Vulnerability Database on July 7, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-26193 actively exploited?
CVE-2026-26193 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 9.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-26193?
CVE-2026-26193 has a CVSS v4.0 base score of 7.3 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-26193?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-26193, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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