Highly exploitable, CVE-2026-18424 poses a critical security risk that could lead to severe breaches.
Status: Analyzed
Last updated: 🕠 21 Sep 2026, 17:50 UTC
Originally published on: 🕗 15 Sep 2026, 20:17 UTC
Time between publication and last update: 5 days
CVSS Release: version 3
nvd@nist.gov
Primary
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N
CVE-2026-18424: Concrete CMS 9.0.0 to 9.5.2 is vulnerable to Server-Side Request Forgery iremote file import via cross-port reuse of a host's validated DNS pin. When multiple remote URLs share the same host, only the first `ValidatedRemoteUrl` is retained and reused for every later URL with that host. A low-privileged authenticated user permitted to import files could therefore supply a DNS-rebinding host that resolved to a public address during validation and to a private or loopback address during the unpinned download, causing the server to fetch internal-only resources such as loopback services, internal admin panels, or cloud metadata endpoints and to save the responses into the file manager. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 2.1 with vector CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N. Thanks Ahmad Wicaksono (sonix03) for reporting.
The exploitability of CVE-2026-18424 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).
This vulnerability, CVE-2026-18424, requires a high level of attack complexity and low privileges, making it difficult but not impossible to exploit. Organizations should ensure robust security configurations to mitigate risks.
A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.
Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.
Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.
Above is the CVSS Sub-score Breakdown for CVE-2026-18424, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.
Below is the Impact Analysis for CVE-2026-18424, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.
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