CVE-2026-63996: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-cwvw-p4x2-27qh
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CVSS 7.8
CWE-787
Published
Advisory Summary

CVE-2026-63996 is a HIGH (CVSS 7.8) security vulnerability vulnerability (CWE-787: Out-of-bounds Write) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product writes data past the end, or before the beginning, of the intended buffer.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-63996 at a Glance

CVE Identifier CVE-2026-63996
GHSA Identifier GHSA-cwvw-p4x2-27qh
Severity HIGH
CVSS v3.1 Base Score 7.8
CWE Classification CWE-787: Out-of-bounds Write
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-2026-63996

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-2026-63996, 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-787: Out-of-bounds Write, where the product writes data past the end, or before the beginning, of the intended 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: ethtool: cmis: require exact CDB reply length Malicious SFP module could respond with rpl_len longer than what cmis_cdb_process_reply() expected, leading to OOB writes. Malicious HW is a bit theoretical but some modules may just be buggy and/or the reads may occasionally get corrupted, so let's protect the kernel. The existing check protects from short replies. We need to protect from long ones, too. All callers that pass a non-zero rpl_exp_len cast the reply payload to a fixed-layout struct and read fields at fixed offsets, with no version negotiation or short-reply handling: - cmis_cdb_validate_password() - cmis_cdb_module_features_get() - cmis_fw_update_fw_mng_features_get() so let's assume that responses longer than expected do not have to be handled gracefully here. Add a warning message to make the debug easier in case my understanding is wrong... Note that page_data->length (argument of kmalloc) comes from last arg to ethtool_cmis_page_init() which is rpl_exp_len. Note2 that AIs also like to point out overflows in args->req.payload itself (which is a fixed-size 120 B buffer, on the stack), but callers should be reading structs defined by the standard, so protecting from requests for more data than max seem like defensive programming.

References

NVD — CVE-2026-63996 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-63996
git.kernel.org/stable/c/2f818cc98f... WEB
https://git.kernel.org/stable/c/2f818cc98fd2c63a08239cb48995f6c3bfe9d9b3
git.kernel.org/stable/c/4d42fb88ec... WEB
https://git.kernel.org/stable/c/4d42fb88ec61f2e98c33a9e3a2de371d5edbc6b1
git.kernel.org/stable/c/6c3f999a9d... WEB
https://git.kernel.org/stable/c/6c3f999a9d1338c6c89a9ff4549eafe72bc2e7b1
git.kernel.org/stable/c/eb5dcd740c... WEB
https://git.kernel.org/stable/c/eb5dcd740cd7fa27bc2caeff2d28ef28e93ff4d3

Frequently Asked Questions

What is CVE-2026-63996?
CVE-2026-63996 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-787: Out-of-bounds Write.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-63996?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-63996?
CVE-2026-63996 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-2026-63996?
CVE-2026-63996 is classified under CWE-787: Out-of-bounds Write (The product writes data past the end, or before the beginning, of the intended buffer.).
How can I check Maven dependencies for CVE-2026-63996?
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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  "id" : "GHSA-cwvw-p4x2-27qh",
  "modified" : "2026-07-20T15:31:54Z",
  "published" : "2026-07-19T18:31:48Z",
  "aliases" : [ "CVE-2026-63996" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nethtool: cmis: require exact CDB reply length\n\nMalicious SFP module could respond with rpl_len longer than\nwhat cmis_cdb_process_reply() expected, leading to OOB writes.\nMalicious HW is a bit theoretical but some modules may just\nbe buggy and/or the reads may occasionally get corrupted,\nso let's protect the kernel.\n\nThe existing check protects from short replies. We need to\nprotect from long ones, too. All callers that pass a non-zero\nrpl_exp_len cast the reply payload to a fixed-layout struct\nand read fields at fixed offsets, with no version negotiation\nor short-reply handling:\n\n  - cmis_cdb_validate_password()\n  - cmis_cdb_module_features_get()\n  - cmis_fw_update_fw_mng_features_get()\n\nso let's assume that responses longer than expected do not\nhave to be handled gracefully here. Add a warning message\nto make the debug easier in case my understanding is wrong...\n\nNote that page_data->length (argument of kmalloc) comes from\nlast arg to ethtool_cmis_page_init() which is rpl_exp_len.\n\nNote2 that AIs also like to point out overflows in args->req.payload\nitself (which is a fixed-size 120 B buffer, on the stack),\nbut callers should be reading structs defined by the standard,\nso protecting from requests for more data than max seem like\ndefensive programming.",
  "severity" : [ {
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