CVE-2026-78553: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-5453-gcx7-h56m
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CWE-276
Published
Advisory Summary

CVE-2026-78553 is a HIGH security vulnerability vulnerability (CWE-276: Incorrect Default Permissions) affecting Software libraries in the Maven ecosystem. The weakness occurs when during installation, installed file permissions are set to allow anyone to modify those files.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-78553 at a Glance

CVE Identifier CVE-2026-78553
GHSA Identifier GHSA-5453-gcx7-h56m
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-276: Incorrect Default Permissions
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

How to Fix CVE-2026-78553

To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-78553, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree

Analyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-276: Incorrect Default Permissions, where during installation, installed file permissions are set to allow anyone to modify those files. In Software, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

RansomLook created its Flask session-signing key without explicitly restricting the file permissions. The secret_key file was created using the process's default permissions and umask, resulting in permissions such as 0644 under a common 022 umask. Consequently, other local users able to access the RansomLook home directory could read the application's cryptographic secret. The exposed key is security-critical because it is used to sign Flask session cookies and is also involved in the legacy API-key key derivation. An attacker who obtains the key can generate valid session cookies and impersonate an authenticated user, including an administrator. In LDAP configurations, exploitation may be particularly straightforward because the session user loader does not require the supplied username to correspond to an existing local user. Successful exploitation requires local access sufficient to read the improperly protected file, but can result in complete compromise of RansomLook's authentication and authorization controls. The patch creates new secret-key files atomically with permissions 0600 and also restricts permissions on existing key files during application startup.

References

NVD — CVE-2026-78553 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-78553
Security Fix Commit FIX COMMIT
https://github.com/RansomLook/RansomLook/commit/df9d47edcf02dd0125db869d5bc19d93f426d892

Frequently Asked Questions

What is CVE-2026-78553?
CVE-2026-78553 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-276: Incorrect Default Permissions.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-78553?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What CWE is associated with CVE-2026-78553?
CVE-2026-78553 is classified under CWE-276: Incorrect Default Permissions (During installation, installed file permissions are set to allow anyone to modify those files.).
How can I check Maven dependencies for CVE-2026-78553?
Run the dependency tree command: 'mvn dependency:tree'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-5453-gcx7-h56m",
  "modified" : "2026-08-24T21:33:45Z",
  "published" : "2026-08-24T21:33:45Z",
  "aliases" : [ "CVE-2026-78553" ],
  "details" : "RansomLook created its Flask session-signing key without explicitly restricting the file permissions. The secret_key file was created using the process's default permissions and umask, resulting in permissions such as 0644 under a common 022 umask. Consequently, other local users able to access the RansomLook home directory could read the application's cryptographic secret.\n\n\nThe exposed key is security-critical because it is used to sign Flask session cookies and is also involved in the legacy API-key key derivation. An attacker who obtains the key can generate valid session cookies and impersonate an authenticated user, including an administrator. In LDAP configurations, exploitation may be particularly straightforward because the session user loader does not require the supplied username to correspond to an existing local user.\n\n\nSuccessful exploitation requires local access sufficient to read the improperly protected file, but can result in complete compromise of RansomLook's authentication and authorization controls.\n\n\nThe patch creates new secret-key files atomically with permissions 0600 and also restricts permissions on existing key files during application startup.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-78553"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/RansomLook/RansomLook/commit/df9d47edcf02dd0125db869d5bc19d93f426d892"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-276" ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-08-24T20:17:24Z"
  }
}