Raw vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:NCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-33953 is a high-severity SSRF (CWE-918) vulnerability in Linkace Linkace. Its CVSS base score is 8.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 20th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to AC-4 (Information Flow Enforcement) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-33953 is a server-side request forgery (SSRF) vulnerability, classified under CWE-918, affecting LinkAce, a self-hosted archive application for collecting website links. Versions prior to 2.5.3 block direct requests to private IP literals but fail to prevent server-side requests to internal-only resources when referenced via internal hostnames. The vulnerability carries a CVSS v3.1 base score of 8.5 (AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N), indicating high severity due to its potential for confidential data exposure across security scopes.
An authenticated user with low privileges can exploit this flaw remotely over the network with low complexity and no user interaction required. By submitting links with internal hostnames, the attacker triggers the LinkAce server to make requests to internal services that are reachable from the server but not exposed externally, potentially allowing unauthorized access to sensitive internal resources and high-impact confidentiality breaches with limited integrity disruption.
The GitHub Security Advisory (GHSA-wp4g-qw9j-wfjg) confirms that LinkAce version 2.5.3 addresses the issue by patching the server-side request handling. Security practitioners should upgrade to version 2.5.3 or later and review access controls for authenticated users to mitigate exploitation risks.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-16868
Vulnerability Data
LinkAce is a self-hosted archive to collect website links. Versions prior to 2.5.3 block direct requests to private IP literals, but still performs server-side requests to internal-only resources when those resources are referenced through an internal hostname. This allows an…
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authenticated user to trigger server-side requests to internal services reachable by the LinkAce server but not directly reachable by an external user. Version 2.5.3 patches the issue.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V1.3.6V1.5.3V5.3.2V10.4.7
Mitigating Controls (NIST 800-53 r5) AI
Information flow enforcement can restrict which destinations the server is allowed to contact on behalf of users.
Input validation directly stops untrusted URLs from being accepted and fetched without destination checks.
Boundary protection limits the network reach of server-initiated requests even if SSRF occurs.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Runtime monitoring of web applications and services can detect anomalous outbound requests indicative of SSRF.
Vulnerability identification processes can discover and record SSRF flaws in web applications.
Network segmentation and egress controls can limit the damage from successful SSRF requests.
Secure development practices directly include input validation and destination allow-listing that prevent SSRF.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Operational threat data describing SSRF campaigns can be used to tighten outbound-request allow-lists and detection rules before attackers exploit them.