Cross-Site Scripting (XSS) in open-webui (CVE-2026-44549)
Summary
Cross-site scripting in open-webui (CVE-2026-44549). Confidential information can be exposed externally. Exploitable via XLSX.utils.sheet_to_html. Mitigation: upgrade to 0.8.0 or later.
Original description
The description as published by the source.
Summary
Excel file attachments are previewed in an unsafe way. A crafted XLSX file payload can be used to cause the sheetjs function sheet_to_html to embed an XSS payload into the generated HTML. This is subsequently added to the DOM unsanitized via @html causing the payload to trigger.
Details
The function used to convert XLSX documents to HTML for preview does not perform any input validation or sanitisation for the generated HTML
https://github.com/open-webui/open-webui/blob/a7271532f8a38da46785afcaa7e65f9a45e7d753/src/lib/components/common/FileItemModal.svelte#L120-L133
XLSX attachments are processed by this function, converted to HTML with XLSX.utils.sheet_to_html before ultimately being assigned to the variable excelHtml. Later there is logic that causes this to be assigned directly to the DOM when the preview tab is selected.
https://github.com/open-webui/open-webui/blob/a7271532f8a38da46785afcaa7e65f9a45e7d753/src/lib/components/common/FileItemModal.svelte#L358-L400
PoC
A python script to generate a payload file is as follows:
import xlsxwriter…
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-44549 has been found in open-webui.
Attackers can target a specific entry point like XLSX.utils.sheet_to_html over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 7.3/10.
What to do: upgrade open-webui to 0.8.0 or later.
If unsure, ask your IT team or search "open-webui CVE-2026-44549" on the vendor's site.
CVE-2026-44549 (open-webui) — CWE-79 / CVSS v3 7.3
Attack vector: remote (network-reachable)
Attack surface: XLSX.utils.sheet_to_html / excelHtml
Patched: 0.8.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Cross-site scripting (XSS) (CWE-79) exists in open-webui. Attackers reach the vulnerable code path via XLSX.utils.sheet_to_html.
Check the vendor advisory for the affected versions of open-webui. Attack surface: XLSX.utils.sheet_to_html / excelHtml.
Severity: High (CVSS 7.3/10). Confidential information can be exposed externally.
Update to 0.8.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'open-webui' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'open-webui' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
open-webuiを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade open-webui to 0.8.0ステージング環境で 0.8.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com