HKUDS LightRAG up to 1.5.4 Markdown Parser parser.py _validated_addresses server-side request forgery

Summaryinfo

A vulnerability categorized as critical has been discovered in HKUDS LightRAG up to 1.5.4. Affected is the function _validated_addresses of the file lightrag/parser/markdown/parser.py of the component Markdown Parser. The manipulation results in server-side request forgery. This vulnerability was named CVE-2026-85740. The attack may be performed from remote. There is no available exploit. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in HKUDS LightRAG up to 1.5.4. Affected is the function _validated_addresses of the file lightrag/parser/markdown/parser.py of the component Markdown Parser. The manipulation with an unknown input leads to a server-side request forgery vulnerability. CWE is classifying the issue as CWE-918. The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

LightRAG provides simple and fast retrieval-augmented generation. Prior to 1.5.5, _validated_addresses in lightrag/parser/markdown/parser.py evaluates the literal resolved address with ipaddress.is_global without consistently classifying an IPv4 address embedded in an IPv6 transition wrapper. A caller who can upload a Markdown or textpack document can supply an external image URL using NAT64 64:ff9b::/96 or an IPv4-compatible form that embeds a loopback, private, or cloud-metadata IPv4 address. On a deployment with compatible NAT64 or DNS64 routing, _download and _build_guarded_opener accept the wrapper and fetch the internal resource, whose body is then ingested. Current interpreter behavior already blocks some RFC 8215 and 6to4 forms, but the fixed guard handles all documented wrappers without becoming more permissive than the standard library. This issue is fixed in version 1.5.5.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-85740 since 09/04/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. There are known technical details, but no exploit is available.

Upgrading to version 1.5.5 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-84549). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Vendor

• HKUDS

Name

• LightRAG

Version

• 1.5.0
• 1.5.1
• 1.5.2
• 1.5.3
• 1.5.4

Website

• Product: https://github.com/HKUDS/LightRAG/

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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