LightRAG: SSRF via IPv6-transition address bypass (NAT64, IPv4-compatible, 6to4) of the native-markdown image-download guard

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-85740
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-22 17:17:27 UTC
Updated2026-09-22 17:17:27 UTC
DescriptionLightRAG 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.

Risk And Classification

Primary CVSS: v3.1 7.1 HIGH from [email protected]

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N

Problem Types: CWE-918 | CWE-918 CWE-918: Server-Side Request Forgery (SSRF)

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.1HIGHCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N
3.1CNADECLARED7.1HIGHCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA HKUDS LightRAG affected < 1.5.5 Not specified

References

ReferenceSourceLinkTags
github.com/HKUDS/LightRAG/commit/9207e7fd10cf6df3cf26e3dd1921490b34a2f132 [email protected] github.com
github.com/HKUDS/LightRAG/pull/3426 [email protected] github.com
github.com/HKUDS/LightRAG/commit/a25862177a9b00e0edb870778a42b4155924de09 [email protected] github.com
github.com/HKUDS/LightRAG/security/advisories/GHSA-vv3m-f8x4-7377 [email protected] github.com
github.com/HKUDS/LightRAG/commit/c598545aa0084a427bcb19a84ade5e0ec31fa673 [email protected] github.com
github.com/HKUDS/LightRAG/releases/tag/v1.5.5 [email protected] github.com
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