CVE-2026-63920: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-8539-cx26-hf58
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CVSS 7.1
CWE-125
Published
Advisory Summary

CVE-2026-63920 is a HIGH (CVSS 7.1) security vulnerability vulnerability (CWE-125: Out-of-bounds Read) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product reads data past the end, or before the beginning, of the intended buffer.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-63920 at a Glance

CVE Identifier CVE-2026-63920
GHSA Identifier GHSA-8539-cx26-hf58
Severity HIGH
CVSS v3.1 Base Score 7.1
CWE Classification CWE-125: Out-of-bounds Read
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 7.1

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:N/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 None (I:N)
Availability High (A:H)

How to Fix CVE-2026-63920

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-2026-63920, 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-125: Out-of-bounds Read, where the product reads 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: ipv6: validate extension header length before copying to cmsg ip6_datagram_recv_specific_ctl() builds IPV6_{HOPOPTS,DSTOPTS,RTHDR} cmsgs (and their IPV6_2292* legacy counterparts) by trusting the on-wire hdrlen byte (ptr[1]) when computing the put_cmsg() length. The length was validated only at parse time (ipv6_parse_hopopts(), etc.). An nftables payload-write expression can rewrite hdrlen after parsing and before the skb reaches recvmsg; the write itself is in-bounds but put_cmsg() then reads up to ((hdrlen+1) << 3) = 2040 bytes from an 8-byte header. nftables is reachable from an unprivileged user namespace, so this is an unprivileged slab-out-of-bounds read: BUG: KASAN: slab-out-of-bounds in put_cmsg+0x3ac/0x540 put_cmsg+0x3ac/0x540 udpv6_recvmsg+0xca0/0x1250 sock_recvmsg+0xdf/0x190 ____sys_recvmsg+0x1b1/0x620 Add ipv6_get_exthdr_len() which validates that at least two bytes are accessible before reading the hdrlen field, then checks the computed length against skb_tail_pointer(skb), returning 0 on failure. Extension headers are kept in the linear skb area by pskb_may_pull() during input, so skb_tail_pointer() is the correct bound. Use ipv6_get_exthdr_len() at all non-AH call sites: the five standalone cmsg blocks (HbH, 2292HbH, 2292DSTOPTS x2, 2292RTHDR) and the three standard cases in the extension-header walk loop (DSTOPTS, ROUTING, default). AH retains an inline bounds check because its length formula differs ((ptr[1]+2)<<2). The walk loop also gets a pre-read bounds check at the top to validate ptr before any case accesses ptr[0] or ptr[1]. When the walk loop detects a corrupted header, return from the function instead of continuing to process later socket options.

References

NVD — CVE-2026-63920 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-63920
git.kernel.org/stable/c/08464413e6... WEB
https://git.kernel.org/stable/c/08464413e628803bd10cb1df68d0138665f2f885
git.kernel.org/stable/c/0d330eff31... WEB
https://git.kernel.org/stable/c/0d330eff318c0f44d4fb0ad2c2aef38f87f24c90
git.kernel.org/stable/c/81394827df... WEB
https://git.kernel.org/stable/c/81394827dfb72772c50d0ae3bdfa094428a5d76d
git.kernel.org/stable/c/931b4a1f13... WEB
https://git.kernel.org/stable/c/931b4a1f13408c2507719890f78f7227c34a0282
git.kernel.org/stable/c/a29768d56e... WEB
https://git.kernel.org/stable/c/a29768d56eb3798c052ad3281b05596e695a17af
git.kernel.org/stable/c/a35daeabb4... WEB
https://git.kernel.org/stable/c/a35daeabb433686234b010ebf7b53778dbd6c9b8
git.kernel.org/stable/c/dd433671fe... WEB
https://git.kernel.org/stable/c/dd433671fef381fdaf7b530c631e6b782d66e224
git.kernel.org/stable/c/eb18a1b164... WEB
https://git.kernel.org/stable/c/eb18a1b1644e4cad978df2131e2bb9a2e6886992

Frequently Asked Questions

What is CVE-2026-63920?
CVE-2026-63920 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-125: Out-of-bounds Read.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-63920?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-63920?
CVE-2026-63920 has a CVSS v3.1 base score of 7.1 (HIGH) with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H.
What CWE is associated with CVE-2026-63920?
CVE-2026-63920 is classified under CWE-125: Out-of-bounds Read (The product reads data past the end, or before the beginning, of the intended buffer.).
How can I check Maven dependencies for CVE-2026-63920?
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-8539-cx26-hf58",
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  "published" : "2026-07-19T18:31:46Z",
  "aliases" : [ "CVE-2026-63920" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: validate extension header length before copying to cmsg\n\nip6_datagram_recv_specific_ctl() builds IPV6_{HOPOPTS,DSTOPTS,RTHDR}\ncmsgs (and their IPV6_2292* legacy counterparts) by trusting the\non-wire hdrlen byte (ptr[1]) when computing the put_cmsg() length.\nThe length was validated only at parse time (ipv6_parse_hopopts(),\netc.).  An nftables payload-write expression can rewrite hdrlen after\nparsing and before the skb reaches recvmsg; the write itself is\nin-bounds but put_cmsg() then reads up to ((hdrlen+1) << 3) = 2040\nbytes from an 8-byte header.  nftables is reachable from an\nunprivileged user namespace, so this is an unprivileged\nslab-out-of-bounds read:\n\n  BUG: KASAN: slab-out-of-bounds in put_cmsg+0x3ac/0x540\n   put_cmsg+0x3ac/0x540\n   udpv6_recvmsg+0xca0/0x1250\n   sock_recvmsg+0xdf/0x190\n   ____sys_recvmsg+0x1b1/0x620\n\nAdd ipv6_get_exthdr_len() which validates that at least two bytes\nare accessible before reading the hdrlen field, then checks the\ncomputed length against skb_tail_pointer(skb), returning 0 on\nfailure.  Extension headers are kept in the linear skb area by\npskb_may_pull() during input, so skb_tail_pointer() is the correct\nbound.\n\nUse ipv6_get_exthdr_len() at all non-AH call sites: the five\nstandalone cmsg blocks (HbH, 2292HbH, 2292DSTOPTS x2, 2292RTHDR)\nand the three standard cases in the extension-header walk loop\n(DSTOPTS, ROUTING, default).  AH retains an inline bounds check\nbecause its length formula differs ((ptr[1]+2)<<2).\n\nThe walk loop also gets a pre-read bounds check at the top to\nvalidate ptr before any case accesses ptr[0] or ptr[1].\n\nWhen the walk loop detects a corrupted header, return from the\nfunction instead of continuing to process later socket options.",
  "severity" : [ {
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}