CVE-2026-100671: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-jcv9-gfgx-wjw4
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CVSS 8.0
CWE-200
Published
Advisory Summary

CVE-2026-100671 is a HIGH (CVSS 8.0) security vulnerability vulnerability (CWE-200: Exposure of Sensitive Information to an Unauthorized Actor) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-100671 at a Glance

CVE Identifier CVE-2026-100671
GHSA Identifier GHSA-jcv9-gfgx-wjw4
Severity HIGH
CVSS v3.1 Base Score 8.0
CWE Classification CWE-200: Exposure of Sensitive Information to an Unauthorized Actor
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 8.0

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction Required (UI:R)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-100671

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-2026-100671, 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-200: Exposure of Sensitive Information to an Unauthorized Actor, where the product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. 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

Grav is a flat-file CMS. In versions 2.0.19 through 2.0.24 — and in 2.0.0 through 2.0.18 and 1.7.x only where content Twig has been explicitly enabled — page content authored by a user holding only page-write permission is rendered through a Twig sandbox that allowlists get_cookie(), which returns any cookie sent with the current request, including the visitor's session cookie. Because the read occurs server-side via filter_input(INPUT_COOKIE, ...), the HttpOnly, Secure and SameSite attributes offer no protection. Grav then stores the finished post-Twig output in a page-content cache keyed only on page identity and the configuration checksum, with no session, user or request dimension and no bypass for authenticated visitors. A page published by a page-write user can therefore capture the session identifier of the next administrator who views it, after which the cached output serves that identifier to unauthenticated visitors, who can replay the cookie to authenticate as that administrator. Since 2.0.19, security.twig_content.process_enabled defaults to true and Security::applyTwigContentDefault() derives each page's process.twig flag from that gate, so content Twig runs on every page with no frontmatter or operator action. Fixed in 2.0.25; 1.7.x is outside the backport scope.

References

GitHub Advisory / Wiki ADVISORY
https://github.com/getgrav/grav/security/advisories/GHSA-pp89-h475-7gj6
NVD — CVE-2026-100671 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-100671
www.vulncheck.com/advisories/grav-bef... WEB
https://www.vulncheck.com/advisories/grav-before-2.0.25-session-cookie-theft-via-twig-sandbox

Frequently Asked Questions

What is CVE-2026-100671?
CVE-2026-100671 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-200: Exposure of Sensitive Information to an Unauthorized Actor.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-100671?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-100671?
CVE-2026-100671 has a CVSS v3.1 base score of 8.0 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-100671?
CVE-2026-100671 is classified under CWE-200: Exposure of Sensitive Information to an Unauthorized Actor (The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.).
How can I check Maven dependencies for CVE-2026-100671?
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-jcv9-gfgx-wjw4",
  "modified" : "2026-09-26T15:31:19Z",
  "published" : "2026-09-26T15:31:19Z",
  "aliases" : [ "CVE-2026-100671" ],
  "details" : "Grav is a flat-file CMS. In versions 2.0.19 through 2.0.24 — and in 2.0.0 through 2.0.18 and 1.7.x only where content Twig has been explicitly enabled — page content authored by a user holding only page-write permission is rendered through a Twig sandbox that allowlists get_cookie(), which returns any cookie sent with the current request, including the visitor's session cookie. Because the read occurs server-side via filter_input(INPUT_COOKIE, ...), the HttpOnly, Secure and SameSite attributes offer no protection. Grav then stores the finished post-Twig output in a page-content cache keyed only on page identity and the configuration checksum, with no session, user or request dimension and no bypass for authenticated visitors. A page published by a page-write user can therefore capture the session identifier of the next administrator who views it, after which the cached output serves that identifier to unauthenticated visitors, who can replay the cookie to authenticate as that administrator. Since 2.0.19, security.twig_content.process_enabled defaults to true and Security::applyTwigContentDefault() derives each page's process.twig flag from that gate, so content Twig runs on every page with no frontmatter or operator action. Fixed in 2.0.25; 1.7.x is outside the backport scope.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:H/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"
  } ],
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  "references" : [ {
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    "url" : "https://github.com/getgrav/grav/security/advisories/GHSA-pp89-h475-7gj6"
  }, {
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  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/grav-before-2.0.25-session-cookie-theft-via-twig-sandbox"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-200" ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-09-26T14:16:50Z"
  }
}