CVE-2026-18743: Software Security Vulnerability Vulnerability

LOW
Advisory Identifier: GHSA-2r56-6h49-5c5r
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CVSS 2.5
CWE-131
Published
Advisory Summary

CVE-2026-18743 is a LOW (CVSS 2.5) security vulnerability vulnerability (CWE-131: Incorrect Calculation of Buffer Size) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product does not correctly calculate the size to be used when allocating a buffer, which could lead to a buffer overflow.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-18743 at a Glance

CVE Identifier CVE-2026-18743
GHSA Identifier GHSA-2r56-6h49-5c5r
Severity LOW
CVSS v3.1 Base Score 2.5
CWE Classification CWE-131: Incorrect Calculation of Buffer Size
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 2.5

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

Attack Vector Local (AV:L)
Attack Complexity High (AC:H)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability Low (A:L)

How to Fix CVE-2026-18743

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-2026-18743, 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-131: Incorrect Calculation of Buffer Size, where the product does not correctly calculate the size to be used when allocating a buffer, which could lead to a buffer overflow. 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

A flaw was found in popt. This vulnerability allows an attacker to provide specially crafted configuration content to a host, which, when loaded, can lead to a small memory corruption issue. This occurs because of an error in how the `poptConfigFileToString` function reallocates memory for buffers. Successful exploitation could result in heap metadata corruption, potentially causing the affected process to become unavailable (denial of service).

References

NVD — CVE-2026-18743 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-18743
access.redhat.com/errata/rhsa-2026:56... WEB
https://access.redhat.com/errata/RHSA-2026:56984
Software Security Information SECURITY
https://access.redhat.com/security/cve/CVE-2026-18743
bugzilla.redhat.com/show_bug.cgi WEB
https://bugzilla.redhat.com/show_bug.cgi?id=2510809

Frequently Asked Questions

What is CVE-2026-18743?
CVE-2026-18743 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-131: Incorrect Calculation of Buffer Size.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-18743?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-18743?
CVE-2026-18743 has a CVSS v3.1 base score of 2.5 (LOW) with vector string CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L.
What CWE is associated with CVE-2026-18743?
CVE-2026-18743 is classified under CWE-131: Incorrect Calculation of Buffer Size (The product does not correctly calculate the size to be used when allocating a buffer, which could lead to a buffer overflow.).
How can I check Maven dependencies for CVE-2026-18743?
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-2r56-6h49-5c5r",
  "modified" : "2026-09-09T00:30:27Z",
  "published" : "2026-09-01T03:31:03Z",
  "aliases" : [ "CVE-2026-18743" ],
  "details" : "A flaw was found in popt. This vulnerability allows an attacker to provide specially crafted configuration content to a host, which, when loaded, can lead to a small memory corruption issue. This occurs because of an error in how the `poptConfigFileToString` function reallocates memory for buffers. Successful exploitation could result in heap metadata corruption, potentially causing the affected process to become unavailable (denial of service).",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-18743"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2026:56984"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/security/cve/CVE-2026-18743"
  }, {
    "type" : "WEB",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2510809"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-131" ],
    "severity" : "LOW",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-09-01T02:16:57Z"
  }
}