CVE-2026-31786: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-7p99-gmjx-2f7r
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CVSS 7.8
CWE-120 CWE-787
Published
Advisory Summary

CVE-2026-31786 is a HIGH (CVSS 7.8) security vulnerability vulnerability (CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-31786 at a Glance

CVE Identifier CVE-2026-31786
GHSA Identifier GHSA-7p99-gmjx-2f7r
Severity HIGH
CVSS v3.1 Base Score 7.8
CWE Classification CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 7.8

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

How to Fix CVE-2026-31786

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-2026-31786, 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-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow'), where the product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer. 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

In the Linux kernel, the following vulnerability has been resolved: Buffer overflow in drivers/xen/sys-hypervisor.c The build id returned by HYPERVISOR_xen_version(XENVER_build_id) is neither NUL terminated nor a string. The first causes a buffer overflow as sprintf in buildid_show will read and copy till it finds a NUL. 00000000 f4 91 51 f4 dd 38 9e 9d 65 47 52 eb 10 71 db 50 |..Q..8..eGR..q.P| 00000010 b9 a8 01 42 6f 2e 32 |...Bo.2| 00000017 So use a memcpy instead of sprintf to have the correct value: 00000000 f4 91 51 f4 dd 00 9e 9d 65 47 52 eb 10 71 db 50 |..Q.....eGR..q.P| 00000010 b9 a8 01 42 |...B| 00000014 (the above have a hack to embed a zero inside and check it's returned correctly). This is XSA-485 / CVE-2026-31786

References

xenbits.xen.org/xsa/advisory-485.ht... WEB
http://xenbits.xen.org/xsa/advisory-485.html
NVD — CVE-2026-31786 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-31786
git.kernel.org/stable/c/27fdbab422... WEB
https://git.kernel.org/stable/c/27fdbab4221b375de54bf91919798d88520c6e28
git.kernel.org/stable/c/4b4defd2fc... WEB
https://git.kernel.org/stable/c/4b4defd2fce3f966c25adabf46644a85558f1169
git.kernel.org/stable/c/52cecff98b... WEB
https://git.kernel.org/stable/c/52cecff98bda2c51eed1c6ce9d21c5d6268fb19d
git.kernel.org/stable/c/5c5ff7c7bd... WEB
https://git.kernel.org/stable/c/5c5ff7c7bd15bb536f44b10b3fb5b8408f344d0a
git.kernel.org/stable/c/8288d031a0... WEB
https://git.kernel.org/stable/c/8288d031a01dbacfde3fc643f7be3d23504de64d
git.kernel.org/stable/c/d5f5921665... WEB
https://git.kernel.org/stable/c/d5f59216650c51e5e3fcb7517c825bc8047f60ef
git.kernel.org/stable/c/e3af585e17... WEB
https://git.kernel.org/stable/c/e3af585e1728c917682b6a3de9a69b41fb9194d4
git.kernel.org/stable/c/f458ba102d... WEB
https://git.kernel.org/stable/c/f458ba102da97fafca106327086fc95f3fc764cb
Software Security Information SECURITY
http://www.openwall.com/lists/oss-security/2026/04/28/12

Frequently Asked Questions

What is CVE-2026-31786?
CVE-2026-31786 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow').
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-31786?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-31786?
CVE-2026-31786 has a CVSS v3.1 base score of 7.8 (HIGH) with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-31786?
CVE-2026-31786 is classified under CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') (The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.).
How can I check Maven dependencies for CVE-2026-31786?
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-7p99-gmjx-2f7r",
  "modified" : "2026-05-04T09:31:08Z",
  "published" : "2026-04-30T12:33:12Z",
  "aliases" : [ "CVE-2026-31786" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nBuffer overflow in drivers/xen/sys-hypervisor.c\n\nThe build id returned by HYPERVISOR_xen_version(XENVER_build_id) is\nneither NUL terminated nor a string.\n\nThe first causes a buffer overflow as sprintf in buildid_show will\nread and copy till it finds a NUL.\n\n00000000  f4 91 51 f4 dd 38 9e 9d  65 47 52 eb 10 71 db 50  |..Q..8..eGR..q.P|\n00000010  b9 a8 01 42 6f 2e 32                              |...Bo.2|\n00000017\n\nSo use a memcpy instead of sprintf to have the correct value:\n\n00000000  f4 91 51 f4 dd 00 9e 9d  65 47 52 eb 10 71 db 50  |..Q.....eGR..q.P|\n00000010  b9 a8 01 42                                       |...B|\n00000014\n\n(the above have a hack to embed a zero inside and check it's\nreturned correctly).\n\nThis is XSA-485 / CVE-2026-31786",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-31786"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/27fdbab4221b375de54bf91919798d88520c6e28"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/4b4defd2fce3f966c25adabf46644a85558f1169"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/52cecff98bda2c51eed1c6ce9d21c5d6268fb19d"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/5c5ff7c7bd15bb536f44b10b3fb5b8408f344d0a"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/8288d031a01dbacfde3fc643f7be3d23504de64d"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/d5f59216650c51e5e3fcb7517c825bc8047f60ef"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/e3af585e1728c917682b6a3de9a69b41fb9194d4"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/f458ba102da97fafca106327086fc95f3fc764cb"
  }, {
    "type" : "WEB",
    "url" : "http://www.openwall.com/lists/oss-security/2026/04/28/12"
  }, {
    "type" : "WEB",
    "url" : "http://xenbits.xen.org/xsa/advisory-485.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-120", "CWE-787" ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-04-30T11:16:20Z"
  }
}