CVE-2026-13221: Software Security Vulnerability Vulnerability

CRITICAL
Advisory Identifier: GHSA-whhx-pv66-xhgq
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CVSS 9.1
CWE-190
Published
Advisory Summary

CVE-2026-13221 is a CRITICAL (CVSS 9.1) security vulnerability vulnerability (CWE-190: Integer Overflow or Wraparound) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. this occurs when an integer value is incremented to a value that is too large to store in the associated representation. when this occurs, the value may become a very small or negative number.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-13221 at a Glance

CVE Identifier CVE-2026-13221
GHSA Identifier GHSA-whhx-pv66-xhgq
Severity CRITICAL
CVSS v3.1 Base Score 9.1
CWE Classification CWE-190: Integer Overflow or Wraparound
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 9.1

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:H/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 High (I:H)
Availability High (A:H)

How to Fix CVE-2026-13221

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-2026-13221, 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-190: Integer Overflow or Wraparound, where the product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. this occurs when an integer value is incremented to a value that is too large to store in the associated representation. when this occurs, the value may become a very small or negative number. 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

Perl versions through 5.43.9 produce silently incorrect regular expression matches when an alternation of more than 65535 fixed string branches is compiled into a trie in Perl_study_chunk. When such branches are combined into a trie, the delta between the first branch and the shared tail is stored in a 16-bit field. A branch count above 65535 overflows the field, and the trie's match decision table is truncated with no warning or error. A pattern of this shape produces false positive matches (matching strings it should not) and false negative matches (failing to match strings it should). When such a pattern gates an access or filtering decision, the result is wrong.

References

NVD — CVE-2026-13221 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-13221
Software Source Repository REPOSITORY
https://github.com/Perl/perl5/issues/23388
Security Fix Commit FIX COMMIT
https://github.com/Perl/perl5/commit/03f74bbbd3a68350d926ee93d56ee4808c28c4c7.patch
Software Security Information SECURITY
http://www.openwall.com/lists/oss-security/2026/07/13/5

Frequently Asked Questions

What is CVE-2026-13221?
CVE-2026-13221 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-190: Integer Overflow or Wraparound.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-13221?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-13221?
CVE-2026-13221 has a CVSS v3.1 base score of 9.1 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H.
What CWE is associated with CVE-2026-13221?
CVE-2026-13221 is classified under CWE-190: Integer Overflow or Wraparound (The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.).
How can I check Maven dependencies for CVE-2026-13221?
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 
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  "schema_version" : "1.4.0",
  "id" : "GHSA-whhx-pv66-xhgq",
  "modified" : "2026-07-14T15:32:09Z",
  "published" : "2026-07-13T18:30:51Z",
  "aliases" : [ "CVE-2026-13221" ],
  "details" : "Perl versions through 5.43.9 produce silently incorrect regular expression matches when an alternation of more than 65535 fixed string branches is compiled into a trie in Perl_study_chunk.\n\nWhen such branches are combined into a trie, the delta between the first branch and the shared tail is stored in a 16-bit field. A branch count above 65535 overflows the field, and the trie's match decision table is truncated with no warning or error.\n\nA pattern of this shape produces false positive matches (matching strings it should not) and false negative matches (failing to match strings it should). When such a pattern gates an access or filtering decision, the result is wrong.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-13221"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/Perl/perl5/issues/23388"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/Perl/perl5/commit/03f74bbbd3a68350d926ee93d56ee4808c28c4c7.patch"
  }, {
    "type" : "WEB",
    "url" : "http://www.openwall.com/lists/oss-security/2026/07/13/5"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-190" ],
    "severity" : "CRITICAL",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-07-13T17:16:48Z"
  }
}