CVE-2026-63836: Software Security Vulnerability Vulnerability

UNKNOWN
Advisory Identifier: GHSA-f3pj-q27g-923q
Share
Published
Advisory Summary

CVE-2026-63836 is a security vulnerability vulnerability (General Security Weakness) affecting Software libraries in the Maven ecosystem. Remediation is available in the latest vendor maintenance releases.

CVE-2026-63836 at a Glance

CVE Identifier CVE-2026-63836
GHSA Identifier GHSA-f3pj-q27g-923q
Severity N/A
CVSS v3.1 Base Score N/A
CWE Classification General Security Weakness
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

How to Fix CVE-2026-63836

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-2026-63836, 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 General Security Weakness. 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: batman-adv: tp_meter: avoid divide-by-zero for dec_cwnd The cwnd is always MSS <= cwnd <= 0x20000000. But the calculation in batadv_tp_update_cwnd() assumes unsigned 32 bit arithmetics. ((mss * 8) ** 2) / (cwnd * 8) In case cwnd is actually 0x20000000, it will be shifted by 3 bit to the left end up at 0x100000000 or U32_MAX + 1. It will therefore wrap around and be 0 - resulting in: ((mss * 8) ** 2) / 0 This is of course invalid and cannot be calculated. The calculation should must be simplified to avoid this overflow: (mss ** 2) * 8 / cwnd It will keep the precision enhancement from the scaling (by 8) but avoid the overflow in the divisor. In theory, there could still be an overflow in the dividend. It is at the moment fixed to BATADV_TP_PLEN in batadv_tp_recv_ack() - so it is not an imminent problem. But allowing it to use the whole u32 bit range, would mean that it can still use up to 67 bits. To keep this calculation safe for 32 bit arithmetic, mss must never use more than floor((32 - 3) / 2) bits - or in other words: must never be larger than 16383.

References

NVD — CVE-2026-63836 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-63836
git.kernel.org/stable/c/1381b021bf... WEB
https://git.kernel.org/stable/c/1381b021bf886b793fa5ffb895a8efae7ba0318f
git.kernel.org/stable/c/33ccd52f3c... WEB
https://git.kernel.org/stable/c/33ccd52f3cc9ed46ce395199f89aa3234dc83314
git.kernel.org/stable/c/35264c4d46... WEB
https://git.kernel.org/stable/c/35264c4d46067d6312871488c810cef387f8c1f6
git.kernel.org/stable/c/585616dab0... WEB
https://git.kernel.org/stable/c/585616dab0aa9c45bc11b2c8082ca78533bc00e9
git.kernel.org/stable/c/7d2a44bc6b... WEB
https://git.kernel.org/stable/c/7d2a44bc6bbe39aed03c68864aa0e54e04a50278
git.kernel.org/stable/c/ac229c86e4... WEB
https://git.kernel.org/stable/c/ac229c86e49fdb96d91f51bc2fa37a9c4f58c44f
git.kernel.org/stable/c/cd74176cf1... WEB
https://git.kernel.org/stable/c/cd74176cf1685f35a2e5f212d15748bbfecb53b6
git.kernel.org/stable/c/d08b69da40... WEB
https://git.kernel.org/stable/c/d08b69da40a101df1e28bfe1e8fa7a09ffa41107

Frequently Asked Questions

What is CVE-2026-63836?
CVE-2026-63836 is a security vulnerability in Software classified as a security vulnerability vulnerability under General Security Weakness.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-63836?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What CWE is associated with CVE-2026-63836?
CVE-2026-63836 is classified under General Security Weakness.
How can I check Maven dependencies for CVE-2026-63836?
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-f3pj-q27g-923q",
  "modified" : "2026-07-19T12:30:24Z",
  "published" : "2026-07-19T12:30:24Z",
  "aliases" : [ "CVE-2026-63836" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: tp_meter: avoid divide-by-zero for dec_cwnd\n\nThe cwnd is always MSS <= cwnd <= 0x20000000. But the calculation in\nbatadv_tp_update_cwnd() assumes unsigned 32 bit arithmetics.\n\n    ((mss * 8) ** 2) / (cwnd * 8)\n\nIn case cwnd is actually 0x20000000, it will be shifted by 3 bit to the\nleft end up at 0x100000000 or U32_MAX + 1. It will therefore wrap around\nand be 0 - resulting in:\n\n    ((mss * 8) ** 2) / 0\n\nThis is of course invalid and cannot be calculated. The calculation should\nmust be simplified to avoid this overflow:\n\n   (mss ** 2) * 8 / cwnd\n\nIt will keep the precision enhancement from the scaling (by 8) but avoid\nthe overflow in the divisor.\n\nIn theory, there could still be an overflow in the dividend. It is at the\nmoment fixed to BATADV_TP_PLEN in batadv_tp_recv_ack() - so it is not an\nimminent problem. But allowing it to use the whole u32 bit range, would\nmean that it can still use up to 67 bits. To keep this calculation safe for\n32 bit arithmetic, mss must never use more than floor((32 - 3) / 2) bits -\nor in other words: must never be larger than 16383.",
  "severity" : [ ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-63836"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/1381b021bf886b793fa5ffb895a8efae7ba0318f"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/33ccd52f3cc9ed46ce395199f89aa3234dc83314"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/35264c4d46067d6312871488c810cef387f8c1f6"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/585616dab0aa9c45bc11b2c8082ca78533bc00e9"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/7d2a44bc6bbe39aed03c68864aa0e54e04a50278"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/ac229c86e49fdb96d91f51bc2fa37a9c4f58c44f"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/cd74176cf1685f35a2e5f212d15748bbfecb53b6"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/d08b69da40a101df1e28bfe1e8fa7a09ffa41107"
  } ],
  "database_specific" : {
    "cwe_ids" : [ ],
    "severity" : null,
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-07-19T12:16:57Z"
  }
}