CVE-2026-63887: Software Security Vulnerability Vulnerability
CRITICALCVE-2026-63887 is a CRITICAL (CVSS 9.8) security vulnerability vulnerability (CWE-122: Heap-based Buffer Overflow) affecting Software libraries in the Maven ecosystem. The weakness occurs when a heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().. Remediation is available in the latest vendor maintenance releases.
CVE-2026-63887 at a Glance
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).
How to Fix CVE-2026-63887
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-2026-63887, 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-122: Heap-based Buffer Overflow, where a heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). 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-2026-63887?
Which Software versions are affected?
What version fixes CVE-2026-63887?
What is the CVSS score of CVE-2026-63887?
What CWE is associated with CVE-2026-63887?
How can I check Maven dependencies for CVE-2026-63887?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-cccw-rxpj-wfqf",
"modified" : "2026-07-20T15:31:50Z",
"published" : "2026-07-19T18:31:44Z",
"aliases" : [ "CVE-2026-63887" ],
"details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nscsi: target: iscsi: Bound iscsi_encode_text_output() appends to rsp_buf\n\niscsi_encode_text_output() concatenates \"key=value\\0\" records into\nlogin->rsp_buf, an 8192-byte kzalloc(MAX_KEY_VALUE_PAIRS) buffer\nallocated in iscsit_alloc_login_setup_buffer(). The three sprintf() call\nsites in this function (lines 1398, 1411, 1424 in v7.1-rc2) never check\nthe remaining buffer capacity:\n\n\t*length += sprintf(output_buf, \"%s=%s\", er->key, er->value);\n\t*length += 1;\n\toutput_buf = textbuf + *length;\n\nThe 8192-byte ceiling at iscsi_target_check_login_request() bounds the\n*input* Login PDU payload, but a single PDU can carry up to 2048 minimal\nfour-byte \"a=b\\0\" pairs, each unknown key expanding to a 16-byte\n\"a=NotUnderstood\\0\" output record via iscsi_add_notunderstood_response().\n2048 * 16 = 32 KiB of output into an 8 KiB buffer, producing a ~24 KiB\nheap overrun in the kmalloc-8k slab.\n\nThe fix introduces a static iscsi_encode_text_record() helper that uses\nsnprintf() with a per-call bounds check against the remaining buffer,\nand threads a u32 textbuf_size parameter through\niscsi_encode_text_output(). Both call sites in\niscsi_target_handle_csg_zero() (PHASE_SECURITY) and\niscsi_target_handle_csg_one() (PHASE_OPERATIONAL) pass\nMAX_KEY_VALUE_PAIRS. On overflow the encoder logs the condition, calls\niscsi_release_extra_responses() to drop queued records, and returns -1;\nboth caller sites now emit ISCSI_STATUS_CLS_INITIATOR_ERR /\nISCSI_LOGIN_STATUS_INIT_ERR via iscsit_tx_login_rsp() before returning,\nso the initiator sees an explicit failed-login response rather than a\nsilent connection drop. (Prior to this patch only the PHASE_OPERATIONAL\ncaller did that; the PHASE_SECURITY caller is converted to the same\nshape.)",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
} ],
"affected" : [ ],
"references" : [ {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-63887"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/26e4a304b7e6f1338c675d527608d32549c091db"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/30bf335e8fe170322080ee001f05ca29c50680b3"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/4e9f0c4a645c995bc75c06c7b3644254ffb4c76b"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/594a40360012ce5f94c715d5e3b20fa3af7d525a"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/b19382dfc6e7dee6d3859ba44b6ca29e97a51627"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/bf33e01f88388c43e285492a63e539df6ffed64c"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/cb84e974fb172bc71386289f37b78ea679410b39"
}, {
"type" : "WEB",
"url" : "https://git.kernel.org/stable/c/efe633e600a0ac68357206fede21b1ac8178f3b8"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-122" ],
"severity" : "CRITICAL",
"github_reviewed" : false,
"github_reviewed_at" : null,
"nvd_published_at" : "2026-07-19T16:17:05Z"
}
}