CVE-2026-63984: Software Security Vulnerability Vulnerability

CRITICAL
Advisory Identifier: GHSA-6hh9-w4p2-c5qm
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CVSS 9.8
CWE-190
Published
Advisory Summary

CVE-2026-63984 is a CRITICAL (CVSS 9.8) security vulnerability vulnerability (CWE-190: Integer Overflow or Wraparound) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. this occurs when an integer value is incremented to a value that is too large to store in the associated representation. when this occurs, the value may become a very small or negative number.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-63984 at a Glance

CVE Identifier CVE-2026-63984
GHSA Identifier GHSA-6hh9-w4p2-c5qm
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-190: Integer Overflow or Wraparound
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 9.8

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

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
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-2026-63984

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-2026-63984, 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-190: Integer Overflow or Wraparound, where the product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. this occurs when an integer value is incremented to a value that is too large to store in the associated representation. when this occurs, the value may become a very small or negative number. 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: ipv6: rpl: fix hdrlen overflow in ipv6_rpl_srh_decompress() ipv6_rpl_srh_decompress() computes: outhdr->hdrlen = (((n + 1) * sizeof(struct in6_addr)) >> 3); hdrlen is __u8. For n >= 127 the result exceeds 255 and silently truncates. With n=127 (cmpri=15, cmpre=15, pad=0, hdrlen=16): (128 * 16) >> 3 = 256, truncated to 0 as __u8 The caller in ipv6_rpl_srh_rcv() then places the compressed header at buf + ((ohdr->hdrlen + 1) << 3). With hdrlen=0 this is buf + 8, but the decompressed region occupies buf[0..2055] (8-byte header plus 128 full addresses). The compressed header overlaps the decompressed data, and ipv6_rpl_srh_compress() writes into this overlap, corrupting the routing header of the forwarded packet. The existing guard at exthdrs.c:546 checks (n + 1) > 255, which prevents n+1 from overflowing unsigned char (the segments_left field), but does not prevent the computed hdrlen from overflowing __u8. n=127 passes because 128 <= 255, yet hdrlen=256 does not fit. Tighten the bound to (n + 1) > 127. This caps n at 126, giving hdrlen = (127 * 16) >> 3 = 254, which fits in __u8. The compressed header then lands at buf + ((254 + 1) << 3) = buf + 2040, exactly past the decompressed region (buf[0..2039]). No overlap. 127 segments is well beyond any realistic RPL deployment.

References

NVD — CVE-2026-63984 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-63984
git.kernel.org/stable/c/3618b34942... WEB
https://git.kernel.org/stable/c/3618b34942b76471d044369bfd30d58c39068bf1
git.kernel.org/stable/c/6fe1cb3120... WEB
https://git.kernel.org/stable/c/6fe1cb312038516cb4d9fa089d700af7059f1a64
git.kernel.org/stable/c/75b3680047... WEB
https://git.kernel.org/stable/c/75b3680047bf09af8e7e471a7a6ddf2ce5847f56
git.kernel.org/stable/c/97e0679136... WEB
https://git.kernel.org/stable/c/97e06791368c01f0ad2a4b3269c2abe19485ca32
git.kernel.org/stable/c/9d5e7a46a9... WEB
https://git.kernel.org/stable/c/9d5e7a46a9f6d8f503b41bfefef70659845f1679
git.kernel.org/stable/c/c0487a9c1e... WEB
https://git.kernel.org/stable/c/c0487a9c1e116cf349e2d1f302d9019670460858
git.kernel.org/stable/c/de02fc0493... WEB
https://git.kernel.org/stable/c/de02fc049352af5a9595f015511222d0a85c326b
git.kernel.org/stable/c/fd238c51b0... WEB
https://git.kernel.org/stable/c/fd238c51b0fa5390cceca9f1ac5a9ffda8063eed

Frequently Asked Questions

What is CVE-2026-63984?
CVE-2026-63984 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-190: Integer Overflow or Wraparound.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-63984?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-63984?
CVE-2026-63984 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-63984?
CVE-2026-63984 is classified under CWE-190: Integer Overflow or Wraparound (The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.).
How can I check Maven dependencies for CVE-2026-63984?
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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  "aliases" : [ "CVE-2026-63984" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: rpl: fix hdrlen overflow in ipv6_rpl_srh_decompress()\n\nipv6_rpl_srh_decompress() computes:\n\n    outhdr->hdrlen = (((n + 1) * sizeof(struct in6_addr)) >> 3);\n\nhdrlen is __u8. For n >= 127 the result exceeds 255 and silently\ntruncates. With n=127 (cmpri=15, cmpre=15, pad=0, hdrlen=16):\n\n    (128 * 16) >> 3 = 256, truncated to 0 as __u8\n\nThe caller in ipv6_rpl_srh_rcv() then places the compressed header\nat buf + ((ohdr->hdrlen + 1) << 3). With hdrlen=0 this is buf + 8,\nbut the decompressed region occupies buf[0..2055] (8-byte header\nplus 128 full addresses). The compressed header overlaps the\ndecompressed data, and ipv6_rpl_srh_compress() writes into this\noverlap, corrupting the routing header of the forwarded packet.\n\nThe existing guard at exthdrs.c:546 checks (n + 1) > 255, which\nprevents n+1 from overflowing unsigned char (the segments_left\nfield), but does not prevent the computed hdrlen from overflowing\n__u8. n=127 passes because 128 <= 255, yet hdrlen=256 does not\nfit.\n\nTighten the bound to (n + 1) > 127. This caps n at 126, giving\nhdrlen = (127 * 16) >> 3 = 254, which fits in __u8. The compressed\nheader then lands at buf + ((254 + 1) << 3) = buf + 2040, exactly\npast the decompressed region (buf[0..2039]). No overlap. 127\nsegments is well beyond any realistic RPL deployment.",
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    "url" : "https://git.kernel.org/stable/c/fd238c51b0fa5390cceca9f1ac5a9ffda8063eed"
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