CVE-2026-62381: Software Security Vulnerability Vulnerability

MODERATE
Advisory Identifier: GHSA-g4fj-xr23-w9hm
Share
CVSS 6.6
CWE-122
Published
Advisory Summary

CVE-2026-62381 is a MODERATE (CVSS 6.6) security vulnerability vulnerability (CWE-122: Heap-based Buffer Overflow) affecting Software libraries in the Maven ecosystem. The weakness occurs when a heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().. Remediation is available in the latest vendor maintenance releases.

CVE-2026-62381 at a Glance

CVE Identifier CVE-2026-62381
GHSA Identifier GHSA-g4fj-xr23-w9hm
Severity MODERATE
CVSS v3.1 Base Score 6.6
CWE Classification CWE-122: Heap-based Buffer Overflow
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 6.6

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

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

How to Fix CVE-2026-62381

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-2026-62381, 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-122: Heap-based Buffer Overflow, where a heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). 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

luci-lib-px5g (LuCI) contains a heap-based buffer overflow in the native ASN.1 encoding routine asn1_add_obj (x509write.c) when signing a certificate with a 2040-bit RSA key. For a 255-byte signature, the BIT STRING allocation is computed from the DER length encoding of 255 bytes, but the payload written after prepending the unused-bits byte is 256 bytes, requiring one additional DER length octet. As a result the allocation is 259 bytes while the tag, length, unused-bits byte, and signature require 260 bytes, and the final memcpy writes one byte beyond the heap buffer. The overflow is reachable through the exported Lua interface via create_selfsigned(); whether it is remotely exploitable depends on the embedding application. The vulnerable code is present on the openwrt-18.06 through openwrt-25.12 release branches and is absent from master, where the luci-lib-px5g package has been removed rather than patched.

References

GitHub Advisory / Wiki ADVISORY
https://github.com/openwrt/luci/security/advisories/GHSA-jgc3-4q3p-g6xh
NVD — CVE-2026-62381 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-62381
www.vulncheck.com/advisories/luci-lib... WEB
https://www.vulncheck.com/advisories/luci-lib-px5g-2040-bit-certificate-signing-heap-buffer-overflow

Frequently Asked Questions

What is CVE-2026-62381?
CVE-2026-62381 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-122: Heap-based Buffer Overflow.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-62381?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-62381?
CVE-2026-62381 has a CVSS v3.1 base score of 6.6 (MODERATE) with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H.
What CWE is associated with CVE-2026-62381?
CVE-2026-62381 is classified under CWE-122: Heap-based Buffer Overflow (A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().).
How can I check Maven dependencies for CVE-2026-62381?
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-g4fj-xr23-w9hm",
  "modified" : "2026-08-22T15:31:03Z",
  "published" : "2026-08-22T15:31:02Z",
  "aliases" : [ "CVE-2026-62381" ],
  "details" : "luci-lib-px5g (LuCI) contains a heap-based buffer overflow in the native ASN.1 encoding routine asn1_add_obj (x509write.c) when signing a certificate with a 2040-bit RSA key. For a 255-byte signature, the BIT STRING allocation is computed from the DER length encoding of 255 bytes, but the payload written after prepending the unused-bits byte is 256 bytes, requiring one additional DER length octet. As a result the allocation is 259 bytes while the tag, length, unused-bits byte, and signature require 260 bytes, and the final memcpy writes one byte beyond the heap buffer. The overflow is reachable through the exported Lua interface via create_selfsigned(); whether it is remotely exploitable depends on the embedding application. The vulnerable code is present on the openwrt-18.06 through openwrt-25.12 release branches and is absent from master, where the luci-lib-px5g package has been removed rather than patched.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/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"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/openwrt/luci/security/advisories/GHSA-jgc3-4q3p-g6xh"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-62381"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/luci-lib-px5g-2040-bit-certificate-signing-heap-buffer-overflow"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-122" ],
    "severity" : "MODERATE",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-08-22T13:16:39Z"
  }
}