CVE-2026-80213: Software Security Vulnerability Vulnerability

MODERATE
Advisory Identifier: GHSA-jr95-x3fr-rcg4
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CVSS 4.0
CWE-197
Published
Advisory Summary

CVE-2026-80213 is a MODERATE (CVSS 4.0) security vulnerability vulnerability (CWE-197: Numeric Truncation Error) affecting Software libraries in the Maven ecosystem. The weakness occurs when truncation errors occur when a primitive is cast to a primitive of a smaller size and data is lost in the conversion.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-80213 at a Glance

CVE Identifier CVE-2026-80213
GHSA Identifier GHSA-jr95-x3fr-rcg4
Severity MODERATE
CVSS v3.1 Base Score 4.0
CWE Classification CWE-197: Numeric Truncation Error
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 4.0

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

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

How to Fix CVE-2026-80213

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-2026-80213, 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-197: Numeric Truncation Error, where truncation errors occur when a primitive is cast to a primitive of a smaller size and data is lost in the conversion. 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

An issue was discovered in the resolv gem before 0.7.2 for Ruby. Resolv::DNS::MessageEncoder wrote a DNS label's length into a single octet without checking its range. A label longer than 255 octets had its length stored modulo 256 but the label data was written unchanged, and thus the bytes on the wire described a different name than the one the application asked to encode. RFC 1035 section 2.3.4 limits a label to 63 octets, and the two high bits of the length octet are reserved for compression pointers. put_string packed the length with put_pack("C", d.length) and put_label used it for labels, and thus any value from 0 to 255 could end up as a label length octet, including the reserved 0x40-0xBF range and the 0xC0-0xFF pointer range. Resolv::DNS::Name.create did not check per-label or total name length either, and thus an attacker-controlled hostname reached the encoder unchanged. An application that resolves an attacker-controlled hostname sends a query whose wire bytes name a domain the attacker chose. A hostname suffix that the application validates against an allowlist becomes padding that never appears on the wire, and thus allowlist and egress checks can be bypassed. The recursive resolver caches the response under the attacker's name, and DNS logs record that name rather than the one the application asked for. A label length whose low octet lands in the 0xC0-0xFF range produces a length octet that conforming parsers read as the start of a compression pointer, with the following attacker-controlled byte as the offset.

References

NVD — CVE-2026-80213 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-80213
Software Source Repository REPOSITORY
https://github.com/ruby/resolv
www.ruby-lang.org/en/news/2026/08/27/... WEB
https://www.ruby-lang.org/en/news/2026/08/27/multiple-vulnerabilities-in-resolv

Frequently Asked Questions

What is CVE-2026-80213?
CVE-2026-80213 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-197: Numeric Truncation Error.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-80213?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-80213?
CVE-2026-80213 has a CVSS v3.1 base score of 4.0 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N.
What CWE is associated with CVE-2026-80213?
CVE-2026-80213 is classified under CWE-197: Numeric Truncation Error (Truncation errors occur when a primitive is cast to a primitive of a smaller size and data is lost in the conversion.).
How can I check Maven dependencies for CVE-2026-80213?
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-jr95-x3fr-rcg4",
  "modified" : "2026-08-27T18:32:25Z",
  "published" : "2026-08-27T18:32:25Z",
  "aliases" : [ "CVE-2026-80213" ],
  "details" : "An issue was discovered in the resolv gem before 0.7.2 for Ruby. Resolv::DNS::MessageEncoder wrote a DNS label's length into a single octet without checking its range. A label longer than 255 octets had its length stored modulo 256 but the label data was written unchanged, and thus the bytes on the wire described a different name than the one the application asked to encode. RFC 1035 section 2.3.4 limits a label to 63 octets, and the two high bits of the length octet are reserved for compression pointers. put_string packed the length with put_pack(\"C\", d.length) and put_label used it for labels, and thus any value from 0 to 255 could end up as a label length octet, including the reserved 0x40-0xBF range and the 0xC0-0xFF pointer range. Resolv::DNS::Name.create did not check per-label or total name length either, and thus an attacker-controlled hostname reached the encoder unchanged. An application that resolves an attacker-controlled hostname sends a query whose wire bytes name a domain the attacker chose. A hostname suffix that the application validates against an allowlist becomes padding that never appears on the wire, and thus allowlist and egress checks can be bypassed. The recursive resolver caches the response under the attacker's name, and DNS logs record that name rather than the one the application asked for. A label length whose low octet lands in the 0xC0-0xFF range produces a length octet that conforming parsers read as the start of a compression pointer, with the following attacker-controlled byte as the offset.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-80213"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ruby/resolv"
  }, {
    "type" : "WEB",
    "url" : "https://www.ruby-lang.org/en/news/2026/08/27/multiple-vulnerabilities-in-resolv"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-197" ],
    "severity" : "MODERATE",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-08-27T17:20:51Z"
  }
}