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LightLLM CVE-2026-103243

| EUVDEUVD-2026-89988 MEDIUM
Server-Side Request Forgery (SSRF) (CWE-918)
2026-09-30 VulnCheck GHSA-26q6-mgpf-f836
6.9
CVSS 4.0 · Vendor: VulnCheck
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Reach exposed LightLLM multimodal endpoint
  2. Delivery
    Submit request with attacker-controlled image_url/audio_url
  3. Exploit
    Server fetches internal URL unvalidated
  4. Execution
    Vision model processes or error reflects response
  5. Impact
    Exfiltrate internal content and network topology

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V4 - API and Web Service URL allowlisting, SSRF prevention
MITRE ATT&CK

2 techniques across 2 tactics: Initial Access, Credential Access

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Requires a LightLLM instance (through v1.2.0) serving multimodal input - i.e. a vision or audio model whose endpoint accepts image_url/audio_url parameters - to be network-reachable by the attacker. No authentication, user interaction, or non-default toggle is needed once such an endpoint is exposed, since the parameters are fetched without validation. Exploitation is LIMITED to deployments that expose multimodal endpoints (text-only serving is not in scope) and yields primarily confidentiality/topology disclosure rather than code execution; realistic impact also depends on what internal services (e.g. cloud metadata, internal APIs) are reachable from the server's network position.

Impact

This is a genuine but moderate-severity issue rather than an urgent, actively-exploited threat. The vendor-supplied CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N, base 6.9) is internally consistent with the description: a network-reachable, low-complexity, unauthenticated SSRF whose primary impact is limited confidentiality - either disclosure of fetched internal content through the vision model or internal network topology inferred from error responses. There is no KEV listing, no EPSS score provided, and no explicitly published exploit code, so exploitation status is 'no public exploit identified at time of analysis' - though the referenced GitHub issue (#1608) and VulnCheck advisory pin down the exact vulnerable code paths (multimodal_utils.py L82-91 and multimodal_params.py L149), which materially lowers the effort to weaponize. The real-world priority is tempered by two factors not captured in the raw score: LightLLM's comparatively narrow deployment footprint, and the requirement that a multimodal (vision/audio) endpoint actually be exposed. No key signals conflict here; the main gap is the absence of EPSS/KEV data, which is expected for a freshly disclosed open-source issue and should not be read as low risk on its own.

Exploit ScenarioDerived

An attacker who can reach an internet-exposed or internal-network LightLLM multimodal endpoint submits an inference request whose image_url or audio_url points at an internal resource (e.g. a cloud metadata endpoint like 169.254.169.254, an internal admin service, or a port-scan target). The server fetches the URL without validation; the vision model's processing of the response, or the differential error messages returned, leak internal content and network topology back to the attacker. No authentication is required and the referenced VulnCheck advisory and GitHub issue identify the exact unvalidated parameters, though no packaged exploit is published.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.4% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 30, 2026

LightLLM through version 1.2.0 accepts image_url and audio_url parameters on its multimodal inference endpoints without validating or restricting the supplied URLs, allowing unauthenticated remote attackers to coerce the server into making arbitrary outbound HTTP requests (CWE-918 server-side request forgery). An attacker who can reach an instance configured to serve a vision or audio model can point those parameters at internal-only resources, and because the fetched content is passed into model processing, the results (or the resulting error messages) can leak internal content and network topology back to the caller. Impact is limited to confidentiality and topology disclosure rather than code execution; the issue is a genuine but moderate-severity exposure, no public exploit code has been identified at time of analysis, and it has not been confirmed actively exploited (no CISA KEV listing). Deployments that only serve text models, or that do not expose multimodal endpoints to untrusted networks, are out of scope.

RemediationAI

No vendor-released patch or fixed version was identified at time of analysis, so remediation must currently rely on compensating controls. First, treat reachability as the primary boundary: do not expose LightLLM multimodal endpoints (the routes consuming image_url/audio_url) to untrusted networks, and place them behind an authenticating reverse proxy or API gateway so that only trusted clients can submit media URLs - the trade-off is that this breaks anonymous access for legitimate integrators. Second, if the multimodal feature is not required, run LightLLM in text-only mode or block the multimodal routes entirely, eliminating the vulnerable code path at the cost of functionality. Third, apply egress filtering on the LightLLM host so the process cannot initiate outbound connections to loopback, RFC1918/internal ranges, link-local and cloud metadata addresses (e.g. 169.254.169.254), or unapproved ports; route legitimate media fetching through a forward proxy with a strict destination allowlist and block redirects to private addresses. Egress filtering is the most effective control against this SSRF class but carries a real side effect: it will block any legitimate remote image or audio URL that lives behind the blocked ranges or requires redirects. Fourth, if code changes are feasible while awaiting an upstream fix, add scheme and host allowlisting plus DNS-resolution checks (reject non-http/https schemes and any URL that resolves to a private address, and re-validate after redirects) in the URL handling that today lives in lightllm/utils/multimodal_utils.py around lines 82-91 and in the parameter definitions in lightllm/server/multimodal_params.py; note that naive deny-list string matching of hostnames is trivially bypassed and should not be relied upon. Finally, monitor the upstream repository and issue tracker for a patched release and upgrade promptly once a fixed version is announced; the references at https://github.com/ModelTC/LightLLM/issues/1608 and https://www.vulncheck.com/advisories/lightllm-through-1.2.0-server-side-request-forgery-via-multimodal-endpoints are the places to watch.

Affected VersionsENISA

LightLLM 0 ≤1.2.0

Affected Packages

euvd lightllm no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The flaw is a classic CWE-918 server-side request forgery rooted in missing input validation of user-controlled URLs. In LightLLM, multimodal request parameters are modeled in lightllm/server/multimodal_params.py (the image_url and audio_url fields, referenced at line 149), and the fetch logic in lightllm/utils/multimodal_utils.py (lines 82-91) retrieves those URLs directly instead of constraining them to a trusted scheme, host, or address range. As a result the LightLLM process itself acts as the HTTP client, so requests originate from the server's network position and can reach loopback addresses, RFC1918 ranges, internal service APIs, and cloud instance metadata endpoints that are unreachable from the attacker's own network. Because the retrieved bytes are subsequently fed to the vision (or audio) model pipeline, an attacker may obtain the fetched content indirectly via model output, and even failures are informative: connection errors, redirects, and timing differences expose internal hostnames, ports, and service availability. The CVSS 4.0 vector supplied with the report (AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N, base 6.9) and the independent assessment (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N) agree on the essentials: unauthenticated network exploitation (PR:N), no user interaction, no integrity or availability impact, low confidentiality loss, and a scope change reflecting that the vulnerable component's trust boundary is crossed to impact other internal systems. The affected product is tracked as cpe:2.3:a:modeltc:lightllm:*:*:*:*:*:*:*:* (ModelTC LightLLM).

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Severity by source

Vendor (VulnCheck) PRIMARY 6.9 MEDIUM
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N
vuln.today AI 5.8 MEDIUM

Unauthenticated network SSRF (PR:N/AV:N/AC:L); scope changes as the server pivots to internal resources (S:C); impact is limited to modest confidentiality/topology disclosure (C:L, I/A:N).

3.1 AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N

Primary rating from Vendor (VulnCheck).

CVSS VectorVendor: VulnCheck

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Vulnerable system: Confidentiality
Low
Vulnerable system: Integrity
None
Vulnerable system: Availability
None
Subsequent system: Confidentiality
Low
Subsequent system: Integrity
None
Subsequent system: Availability
None

DescriptionCVE.org

LightLLM through 1.2.0 fails to validate image_url and audio_url parameters in multimodal endpoints, allowing unauthenticated attackers to perform server-side request forgery. Attackers can supply arbitrary URLs to fetch internal resources, with vision model processing disclosing content or error responses revealing internal network topology.

Threat Intelligence Overview

EPSS Score
0.4%
Top 67% exploitable
Prevalence
Low
niche open-source LLM inference server, limited production footprint versus vLLM/TGI
Data Quality
5 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.4%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation
Poc
System Exposure· derived
Open
Automatable
Yes
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

34
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +34
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Server-Side Request Forgery exploits applications that fetch remote resources based on user-supplied URLs.

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