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Vulnerability-Lookup CVE-2026-73432

| EUVDEUVD-2026-57231 MEDIUM
Server-Side Request Forgery (SSRF) (CWE-918)
2026-08-12 CIRCL GHSA-wx9v-ffw3-45wg
5.1
CVSS 4.0 · Vendor: CIRCL
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Attack ChainAIDerived

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

  1. Access
    Obtain admin:access credentials
  2. Delivery
    Configure remote instance URL targeting internal or metadata address (direct or via public redirector)
  3. Exploit
    Trigger synchronization (scheduled or manual)
  4. Execution
    Sync worker issues HTTP GET from server's network context
  5. Persist
    Receive response from internal service or cloud metadata endpoint
  6. Impact
    Exfiltrate credentials or probe internal services

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

Exploitation requires a valid authenticated session with the admin:access permission - a high-privilege administrative role, not a standard user account. The remote instance synchronization feature must be in use (it is a standard application capability, not a non-default configuration). Actual confidentiality and integrity impact depends entirely on which services are reachable from the Vulnerability-Lookup application server's network position: cloud-hosted deployments with accessible instance metadata endpoints (169.254.169.254) face meaningful credential-theft risk, while deployments with no significant adjacent internal services face lower practical impact. No victim interaction is required beyond the attacker's own administrative actions. The redirect-chain bypass extends exploitation to any public URL that redirects to an internal destination, removing the need for the admin to directly specify a private IP. Exploitation is limited by the HTTP/HTTPS scheme requirement of the pre-patch validator (non-HTTP schemes such as file:// or gopher:// were already rejected).

Impact

The CVSS 4.0 score of 5.1 (Medium) is well-calibrated for this vulnerability. The PR:H metric is determinative: exploitation is gated on possession of a valid admin:access session, substantially reducing the realistic attacker population compared to unauthenticated SSRF. AV:N/AC:L confirm that once admin credentials are obtained, exploitation is straightforward and network-accessible with low complexity. The provided CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N) is consistent with the description and aligns with this analyst's independent assessment. EPSS data was not supplied; given no KEV listing and no known public exploit, exploitation probability is presumed low. Real-world severity is highly deployment-context-dependent: a cloud-hosted instance with an accessible AWS/GCP/Azure metadata endpoint (169.254.169.254) is meaningfully more exposed than an air-gapped on-premises deployment, because metadata credential theft could lead to IAM privilege escalation far beyond the application. The redirect-chain bypass modestly elevates practical exploitability beyond a naive static-URL check. This vulnerability is not a broad mass-exploitation risk, but any operator running Vulnerability-Lookup in a cloud VPC or alongside sensitive internal network services should treat the patch as urgent regardless of the medium CVSS score.

Exploit ScenarioDerived

An attacker who has obtained admin:access credentials - whether through credential theft, phishing, or insider access - navigates to the remote instance configuration interface and registers a new peer instance pointing to http://169.254.169.254/latest/meta-data/ or to a public redirector service that chains to that address. When the scheduled or manually triggered synchronization worker runs, the Vulnerability-Lookup application server issues an HTTP GET from its own network context, potentially returning AWS EC2 instance metadata including attached IAM role temporary credentials. No public proof-of-concept code has been identified, but SSRF-to-cloud-metadata is a well-documented and widely understood attack pattern.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Aug 12, 2026

Server-side request forgery in Vulnerability-Lookup's remote-instance synchronization feature enables an authenticated administrator holding the admin:access permission to pivot HTTP requests through the application server's network context. By registering a remote instance whose address resolves to a loopback, private, link-local, or cloud metadata endpoint - or by using a public URL that redirects to such a destination - the attacker causes the background sync worker to issue HTTP GET requests from the server's own network position, potentially exposing internal services or cloud instance metadata credentials. No public exploit has been identified at time of analysis and the vulnerability is not listed in the CISA KEV catalog; a patch is available as an upstream commit from CIRCL.

RemediationAI

Apply the upstream patch available at https://github.com/vulnerability-lookup/vulnerability-lookup/commit/a3cf621c2583c45227a5b7880123ba0ffef3cc0f, which introduces a shared outbound URL policy (website/lib/remote_url.py) enforcing HTTP/HTTPS-only schemes, blocking all private, loopback, link-local, multicast, reserved, and unspecified IP addresses at both configuration time and per-request time, and manually validating each redirect destination before following it. A specific patched release version has not been independently confirmed from available data - verify with CIRCL or the upstream project for the first tagged release containing this commit. As an interim compensating control, restrict the admin:access role to the absolute minimum number of trusted accounts and audit all currently configured remote instance URLs for addresses in private or metadata ranges. Deploying a network egress filter or forward proxy that allowlists only approved external Vulnerability-Lookup instance addresses will prevent the server from reaching internal ranges even if misconfiguration occurs, at the cost of requiring explicit allowlist maintenance for each legitimate peer instance.

Affected VersionsENISA

Vulnerability-Lookup 0 ≤5.5.1

Affected Packages

euvd vulnerability_lookup 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

Vulnerability-Lookup is a threat intelligence aggregation platform developed by CIRCL (CPE: cpe:2.3:a:vulnerability-lookup:vulnerability-lookup:*:*:*:*:*:*:*:*) that supports synchronization with remote Vulnerability-Lookup instances. The root cause is CWE-918 (Server-Side Request Forgery): a validation gap existed between the point of URL storage and the point of URL dereferencing. At configuration time, remote instance addresses were checked only against a basic regex pattern confirming HTTP/HTTPS scheme and host presence (^https?://[^\s/$.?#].[^\s]*$), with no network-boundary enforcement. At request time, the sync worker called Python's requests.get() with automatic redirect following and no filtering for RFC-1918 private space (10.x, 192.168.x, 172.16-31.x), loopback (127.0.0.1, ::1), link-local (169.254.x.x), multicast, or reserved addresses. The redirect chain bypass compounded the exposure: an attacker could register a publicly routable URL that issues a 301/302/307/308 redirect to an internal target, because each redirect destination was followed without re-validation. The patch (commit a3cf621c2583c45227a5b7880123ba0ffef3cc0f) introduces website/lib/remote_url.py, a shared outbound URL policy that enforces HTTP/HTTPS scheme allowlisting, validates IP literals at configuration time, resolves hostnames via getaddrinfo at request time, and manually walks each redirect hop through the same public-IP check before following it.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (CIRCL) PRIMARY 5.1 MEDIUM
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
vuln.today AI 5.5 MEDIUM

Admin-only prerequisite sets PR:H; scope change (S:C) reflects server pivoting to otherwise-unreachable internal services; no availability impact identified.

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

Primary rating from Vendor (CIRCL).

CVSS VectorVendor: CIRCL

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

DescriptionCVE.org

Vulnerability-Lookup contains a server-side request forgery (SSRF) vulnerability in the remote-instance synchronization functionality. Remote instance addresses were validated only for basic URL syntax before being stored, while the synchronization worker later dereferenced these addresses using requests.get() with automatic redirect handling and without enforcing network-boundary restrictions.

An authenticated administrator with the admin:access permission could configure a remote instance whose address points to an internal, loopback, link-local, or cloud metadata HTTP(S) service. When synchronization is performed, the Vulnerability-Lookup server would issue the request from its own network context. An attacker could also use a publicly accessible URL that redirects to an internal destination, because redirects were previously followed without revalidating the destination.

Successful exploitation could allow a privileged attacker to probe or interact with services that are accessible from the Vulnerability-Lookup server but not directly reachable by the attacker, including private network services or cloud instance metadata endpoints. The exact confidentiality, integrity, or availability impact depends on the services reachable from the application server.

The patch introduces a shared outbound URL policy that restricts remote instances to HTTP(S), rejects non-public IP addresses, resolves hostnames at request time, and manually validates each redirect destination before following it. The implementation explicitly blocks private, loopback, link-local, multicast, reserved, and unspecified addresses.

Threat Intelligence Overview

EPSS Score
0.2%
Top 84% exploitable
Prevalence
Low
niche security intelligence platform, limited enterprise footprint
Data Quality
6 sources
Confidence: High

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 0.2%
Patch available Yes
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
None
System Exposure· derived
Open
Automatable
No
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

26
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +26
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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