If left unpatched, CVE-2026-40255 could lead to major system disruptions or data loss.
Status: Received on 16 Apr 2026, 23:16 UTC
Published on: 16 Apr 2026, 23:16 UTC
CVSS Release: version 3
security-advisories@github.com
Secondary
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CVE-2026-40255: AdonisJS HTTP Server is a package for handling HTTP requests in the AdonisJS framework. In @adonisjs/http-server versions prior to 7.8.1 and 8.0.0-next.0 through 8.1.3, and @adonisjs/core versions prior to 7.4.0, the response.redirect().back() method reads the Referer header from the incoming HTTP request and redirects to that URL without validating the host.An attacker who can influence the Referer header can cause the application to redirect users to a malicious external site. This affects all AdonisJS applications that use response.redirect().back() or response.redirect('back'). This issue has been fixed in versions 7.8.1 and 8.2.0 and 7.4.0 of @adonisjs/core.
The exploitability of CVE-2026-40255 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).
With low attack complexity and no required privileges, CVE-2026-40255 is an easy target for cybercriminals. Organizations should prioritize immediate mitigation measures to prevent unauthorized access and data breaches.
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-2026-40255, 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-2026-40255, 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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