CVE-2026-31504: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-5v9p-3rfc-6rw2
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CVSS 7.8
CWE-362 CWE-416
Published
Advisory Summary

CVE-2026-31504 is a HIGH (CVSS 7.8) security vulnerability vulnerability (CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-31504 at a Glance

CVE Identifier CVE-2026-31504
GHSA Identifier GHSA-5v9p-3rfc-6rw2
Severity HIGH
CVSS v3.1 Base Score 7.8
CWE Classification CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
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-2026-31504

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-2026-31504, 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-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition'), where the product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently. 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: net: fix fanout UAF in packet_release() via NETDEV_UP race `packet_release()` has a race window where `NETDEV_UP` can re-register a socket into a fanout group's `arr[]` array. The re-registration is not cleaned up by `fanout_release()`, leaving a dangling pointer in the fanout array. `packet_release()` does NOT zero `po->num` in its `bind_lock` section. After releasing `bind_lock`, `po->num` is still non-zero and `po->ifindex` still matches the bound device. A concurrent `packet_notifier(NETDEV_UP)` that already found the socket in `sklist` can re-register the hook. For fanout sockets, this re-registration calls `__fanout_link(sk, po)` which adds the socket back into `f->arr[]` and increments `f->num_members`, but does NOT increment `f->sk_ref`. The fix sets `po->num` to zero in `packet_release` while `bind_lock` is held to prevent NETDEV_UP from linking, preventing the race window. This bug was found following an additional audit with Claude Code based on CVE-2025-38617.

References

NVD — CVE-2026-31504 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-31504
cert-portal.siemens.com/productcert/html/ss... WEB
https://cert-portal.siemens.com/productcert/html/ssa-019113.html
cert-portal.siemens.com/productcert/html/ss... WEB
https://cert-portal.siemens.com/productcert/html/ssa-082556.html
cert-portal.siemens.com/productcert/html/ss... WEB
https://cert-portal.siemens.com/productcert/html/ssa-457936.html
git.kernel.org/stable/c/1b4c03f889... WEB
https://git.kernel.org/stable/c/1b4c03f8892d955385c202009af7485364731bb9
git.kernel.org/stable/c/42156f93d1... WEB
https://git.kernel.org/stable/c/42156f93d123436f2a27c468f18c966b7e5db796
git.kernel.org/stable/c/42cfd7898e... WEB
https://git.kernel.org/stable/c/42cfd7898eeed290c9fb73f732af1f7d6b0a703e
git.kernel.org/stable/c/654386baef... WEB
https://git.kernel.org/stable/c/654386baef228c2992dbf604c819e4c7c35fc71b
git.kernel.org/stable/c/75fe6db237... WEB
https://git.kernel.org/stable/c/75fe6db23705a1d55160081f7b37db9665b1880b
git.kernel.org/stable/c/ceccbfc6de... WEB
https://git.kernel.org/stable/c/ceccbfc6de720ad633519a226715989cfb065af1
git.kernel.org/stable/c/d0c7cdc15f... WEB
https://git.kernel.org/stable/c/d0c7cdc15fdf8c4f91aca1928e52295d175b6ec6
git.kernel.org/stable/c/ee642b1962... WEB
https://git.kernel.org/stable/c/ee642b1962caa9aa231c01abbd58bc453ae6b66e

Frequently Asked Questions

What is CVE-2026-31504?
CVE-2026-31504 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition').
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-31504?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-31504?
CVE-2026-31504 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-2026-31504?
CVE-2026-31504 is classified under CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') (The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.).
How can I check Maven dependencies for CVE-2026-31504?
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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  "published" : "2026-04-22T15:31:43Z",
  "aliases" : [ "CVE-2026-31504" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: fix fanout UAF in packet_release() via NETDEV_UP race\n\n`packet_release()` has a race window where `NETDEV_UP` can re-register a\nsocket into a fanout group's `arr[]` array. The re-registration is not\ncleaned up by `fanout_release()`, leaving a dangling pointer in the fanout\narray.\n`packet_release()` does NOT zero `po->num` in its `bind_lock` section.\nAfter releasing `bind_lock`, `po->num` is still non-zero and `po->ifindex`\nstill matches the bound device. A concurrent `packet_notifier(NETDEV_UP)`\nthat already found the socket in `sklist` can re-register the hook.\nFor fanout sockets, this re-registration calls `__fanout_link(sk, po)`\nwhich adds the socket back into `f->arr[]` and increments `f->num_members`,\nbut does NOT increment `f->sk_ref`.\n\nThe fix sets `po->num` to zero in `packet_release` while `bind_lock` is\nheld to prevent NETDEV_UP from linking, preventing the race window.\n\nThis bug was found following an additional audit with Claude Code based\non CVE-2025-38617.",
  "severity" : [ {
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    "url" : "https://cert-portal.siemens.com/productcert/html/ssa-019113.html"
  }, {
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    "url" : "https://cert-portal.siemens.com/productcert/html/ssa-082556.html"
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    "url" : "https://git.kernel.org/stable/c/75fe6db23705a1d55160081f7b37db9665b1880b"
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