CVE-2026-64009: Software Security Vulnerability Vulnerability
HIGHCVE-2026-64009 is a HIGH (CVSS 7.8) security vulnerability vulnerability (CWE-191: Integer Underflow (Wrap or Wraparound)) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result.. Remediation is available in the latest vendor maintenance releases.
CVE-2026-64009 at a Glance
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).
How to Fix CVE-2026-64009
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.
Run the following command in your project directory to verify that all resolved dependencies use the patched release:
mvn dependency:treeHow to Check if You Are Affected
To determine whether your Java application is affected by CVE-2026-64009, inspect your build dependencies using the Maven Dependency Plugin:
mvn dependency:treeAnalyze 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-191: Integer Underflow (Wrap or Wraparound), where the product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result. 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
References
Frequently Asked Questions
What is CVE-2026-64009?
Which Software versions are affected?
What version fixes CVE-2026-64009?
What is the CVSS score of CVE-2026-64009?
What CWE is associated with CVE-2026-64009?
How can I check Maven dependencies for CVE-2026-64009?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-666q-fgc6-3x4w",
"modified" : "2026-07-20T15:31:55Z",
"published" : "2026-07-19T18:31:49Z",
"aliases" : [ "CVE-2026-64009" ],
"details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: Check for underflow in xfrm_state_mtu\n\nLeo Lin reported OOB write issue in esp component:\n\n xfrm_state_mtu() returns u32 but performs its arithmetic in unsigned\n modulo-2^32 space using an attacker-influenced \"header_len + authsize +\n net_adj\" subtracted from a small \"mtu\" argument. A nobody user can\n install an IPv4 ESP tunnel SA with a large authentication key\n (XFRMA_ALG_AUTH_TRUNC, e.g. hmac(sha512), 64-byte key, 64-byte trunc),\n configure a small interface MTU (68 bytes), and set XFRMA_TFCPAD to a\n large value. When a single UDP datagram is then sent through the\n tunnel, xfrm_state_mtu() underflows to a near-2^32 value, and\n esp_output() consumes it as a signed int via:\n\n padto = min(x->tfcpad, xfrm_state_mtu(x, mtu_cached))\n esp.tfclen = padto - skb->len (assigned to int)\n\n esp.tfclen ends up negative (e.g. -207). It is sign-extended to size_t\n when passed to memset() inside esp_output_fill_trailer(), producing a\n ~16 EB write of zeroes at skb_tail_pointer(skb). KASAN logs it as\n \"Write of size 18446744073709551537 at addr ffff888...\".\n\nCheck for underflow and return 1. This causes the sendmsg attempt to\nfail with ENETUNREACH.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
} ],
"affected" : [ ],
"references" : [ {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-64009"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/1021d2877b689a648b27815c854557a917122e93"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/2a41b1b31c61c52b972278ce1732a1443f5e89ed"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/3db50ceeacb52806d8fe86fb1dfe944df0b9f789"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/742b04d0550b0ec89dcbc99537ec88653bd1ad90"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/8014f70c4e6e5ab101ae3860a614e65e988372e3"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/820e501be8aee4b365d218d83227b314309c5fda"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/82ac903e0b519849647657b8c48d21237ada06a2"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/fccd685b32df5aaf6bad4381eeda216468e283f0"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-191", "CWE-787" ],
"severity" : "HIGH",
"github_reviewed" : false,
"github_reviewed_at" : null,
"nvd_published_at" : "2026-07-19T16:17:40Z"
}
}