unstructured: URL Redirection to Untrusted Site
CVE-2026-71428 is a critical-severity URL redirection to untrusted site vulnerability in unstructured from Unstructured-IO, with a CVSS 3.1 base score of 9.3 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected unstructured versions: >= 0.4.7, < 0.24.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.44% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of unstructured you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Unstructured-IO | unstructured | >= 0.4.7, < 0.24.0 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- LowLimited modification of data is possible.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N. Scored by CNA (github.com).
Official description
The unstructured library provides open-source components for ingesting and pre-processing images and text documents, such as PDFs, HTML, Word docs, and many more. From 0.4.7 until 0.24.0, the url argument of partition, partition_html, and partition_md is fetched without host validation in unstructured/partition/auto.py, unstructured/partition/html/partition.py, and unstructured/partition/md.py. An attacker who controls that URL can make a server-side ingestion service request loopback addresses, internal HTTP services, or cloud metadata endpoints through direct targets, redirects, or DNS rebinding. The response body is returned as Element text, allowing internal response disclosure, and side-effecting GET endpoints may also be triggered. This issue is fixed in version 0.24.0.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: URL Redirection to Untrusted Site
The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.
How developers prevent this class of flaw
- Use an intermediate disclaimer page that provides the user with a clear warning that they are leaving the current site. Implement a long timeout before the redirect occurs, or force the user to click on the link. Be careful to avoid XSS problems (CWE-79) when generating the disclaimer page.
- When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs. For example, ID 1 could map to /login.asp and ID 2 could map to http://www.example.com/. Features such as the ESAPI AccessReferenceMap provide this capability.
- Ensure that no externally-supplied requests are honored by requiring that all redirect requests include a unique nonce generated by the application. Be sure that the nonce is not predictable (CWE-330).
More URL Redirection to Untrusted Site vulnerabilities (CWE-601)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other vulnerabilities in unstructured
- 9.8 Critical severity
Recent URL Redirection to Untrusted Site vulnerabilities
- 9.6 Critical severity
- 7.0 High severity
- 7.1 High severity
- 7.5 High severity
- 7.8 High severity
- 7.5 High severity
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