CVE-2026-87079: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-vx57-287r-4h84
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CVSS 7.5
CWE-407
Published
Advisory Summary

CVE-2026-87079 is a HIGH (CVSS 7.5) security vulnerability vulnerability (CWE-407: Inefficient Algorithmic Complexity) affecting Software libraries in the Maven ecosystem. The weakness occurs when an algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-87079 at a Glance

CVE Identifier CVE-2026-87079
GHSA Identifier GHSA-vx57-287r-4h84
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-407: Inefficient Algorithmic Complexity
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 7.5

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

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

How to Fix CVE-2026-87079

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-2026-87079, 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-407: Inefficient Algorithmic Complexity, where an algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached. 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

Net::IDN::Punycode versions before 2.590 for Perl allow CPU exhaustion via quadratic insertion cost when decoding a long label in decode_punycode. The XS backend inserts each decoded code point into a UTF-8 buffer and finds the insertion point by scanning that buffer from the start, one character at a time. The scan runs once per code point over the output built so far, so the cost is quadratic in the label length. The pure-Perl backend downgrades its input to bytes so that substr can index it directly, but takes its working copy before the downgrade, so when the input carries the UTF-8 flag every substr on the copy scans from the start, with the same quadratic cost. Nothing bounds the label length in the to-Unicode direction. The 63-byte DNS limit is checked only when converting to ASCII, so domain_to_unicode and uts46_to_unicode pass an attacker-supplied label of any length to the decoder.

References

NVD — CVE-2026-87079 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-87079
Security Fix Commit FIX COMMIT
https://github.com/robrwo/Net-IDN-Encode/commit/00d723423b66810af26b88c552bedc61975b3078.patch
Security Fix Commit FIX COMMIT
https://github.com/robrwo/Net-IDN-Encode/commit/447c6b38ef5d4570329fa4f78690f4e14e09ba0c.patch
metacpan.org/release/pjcj/net-id... WEB
https://metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes
Software Security Information SECURITY
http://www.openwall.com/lists/oss-security/2026/09/22/14

Frequently Asked Questions

What is CVE-2026-87079?
CVE-2026-87079 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-407: Inefficient Algorithmic Complexity.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-87079?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-87079?
CVE-2026-87079 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2026-87079?
CVE-2026-87079 is classified under CWE-407: Inefficient Algorithmic Complexity (An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.).
How can I check Maven dependencies for CVE-2026-87079?
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-vx57-287r-4h84",
  "modified" : "2026-09-22T18:33:28Z",
  "published" : "2026-09-22T09:31:12Z",
  "aliases" : [ "CVE-2026-87079" ],
  "details" : "Net::IDN::Punycode versions before 2.590 for Perl allow CPU exhaustion via quadratic insertion cost when decoding a long label in decode_punycode.\n\nThe XS backend inserts each decoded code point into a UTF-8 buffer and finds the insertion point by scanning that buffer from the start, one character at a time. The scan runs once per code point over the output built so far, so the cost is quadratic in the label length. The pure-Perl backend downgrades its input to bytes so that substr can index it directly, but takes its working copy before the downgrade, so when the input carries the UTF-8 flag every substr on the copy scans from the start, with the same quadratic cost.\n\nNothing bounds the label length in the to-Unicode direction. The 63-byte DNS limit is checked only when converting to ASCII, so domain_to_unicode and uts46_to_unicode pass an attacker-supplied label of any length to the decoder.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-87079"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/robrwo/Net-IDN-Encode/commit/00d723423b66810af26b88c552bedc61975b3078.patch"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/robrwo/Net-IDN-Encode/commit/447c6b38ef5d4570329fa4f78690f4e14e09ba0c.patch"
  }, {
    "type" : "WEB",
    "url" : "https://metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes"
  }, {
    "type" : "WEB",
    "url" : "http://www.openwall.com/lists/oss-security/2026/09/22/14"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-407" ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-09-22T08:16:40Z"
  }
}