CVE-2025-21756: Software Security Vulnerability Vulnerability

HIGH

Advisory Identifier: GHSA-5828-2c94-235c

CVSS 7.8

Published 2025-02-27

Advisory Summary

CVE-2025-21756 is a HIGH (CVSS 7.8) security vulnerability vulnerability (CWE-416: Use After Free) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product reuses or references memory after it has been freed. at some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.. Remediation is available in the latest vendor maintenance releases.

CVE-2025-21756 at a Glance

CVE Identifier CVE-2025-21756

GHSA Identifier GHSA-5828-2c94-235c

Severity HIGH

CVSS v3.1 Base Score 7.8

CWE Classification CWE-416: Use After Free

Affected Product Software

Package Ecosystem Maven

Published Date 2025-02-27

Last Updated 2026-10-15

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-2025-21756

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-2025-21756, 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-416: Use After Free, where the product reuses or references memory after it has been freed. at some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer. 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: vsock: Keep the binding until socket destruction Preserve sockets bindings; this includes both resulting from an explicit bind() and those implicitly bound through autobind during connect(). Prevents socket unbinding during a transport reassignment, which fixes a use-after-free: 1. vsock_create() (refcnt=1) calls vsock_insert_unbound() (refcnt=2) 2. transport->release() calls vsock_remove_bound() without checking if sk was bound and moved to bound list (refcnt=1) 3. vsock_bind() assumes sk is in unbound list and before __vsock_insert_bound(vsock_bound_sockets()) calls __vsock_remove_bound() which does: list_del_init(&vsk->bound_table); // nop sock_put(&vsk->sk); // refcnt=0 BUG: KASAN: slab-use-after-free in __vsock_bind+0x62e/0x730 Read of size 4 at addr ffff88816b46a74c by task a.out/2057 dump_stack_lvl+0x68/0x90 print_report+0x174/0x4f6 kasan_report+0xb9/0x190 __vsock_bind+0x62e/0x730 vsock_bind+0x97/0xe0 __sys_bind+0x154/0x1f0 __x64_sys_bind+0x6e/0xb0 do_syscall_64+0x93/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e Allocated by task 2057: kasan_save_stack+0x1e/0x40 kasan_save_track+0x10/0x30 __kasan_slab_alloc+0x85/0x90 kmem_cache_alloc_noprof+0x131/0x450 sk_prot_alloc+0x5b/0x220 sk_alloc+0x2c/0x870 __vsock_create.constprop.0+0x2e/0xb60 vsock_create+0xe4/0x420 __sock_create+0x241/0x650 __sys_socket+0xf2/0x1a0 __x64_sys_socket+0x6e/0xb0 do_syscall_64+0x93/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e Freed by task 2057: kasan_save_stack+0x1e/0x40 kasan_save_track+0x10/0x30 kasan_save_free_info+0x37/0x60 __kasan_slab_free+0x4b/0x70 kmem_cache_free+0x1a1/0x590 __sk_destruct+0x388/0x5a0 __vsock_bind+0x5e1/0x730 vsock_bind+0x97/0xe0 __sys_bind+0x154/0x1f0 __x64_sys_bind+0x6e/0xb0 do_syscall_64+0x93/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e refcount_t: addition on 0; use-after-free. WARNING: CPU: 7 PID: 2057 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150 RIP: 0010:refcount_warn_saturate+0xce/0x150 __vsock_bind+0x66d/0x730 vsock_bind+0x97/0xe0 __sys_bind+0x154/0x1f0 __x64_sys_bind+0x6e/0xb0 do_syscall_64+0x93/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e refcount_t: underflow; use-after-free. WARNING: CPU: 7 PID: 2057 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150 RIP: 0010:refcount_warn_saturate+0xee/0x150 vsock_remove_bound+0x187/0x1e0 __vsock_release+0x383/0x4a0 vsock_release+0x90/0x120 __sock_release+0xa3/0x250 sock_close+0x14/0x20 __fput+0x359/0xa80 task_work_run+0x107/0x1d0 do_exit+0x847/0x2560 do_group_exit+0xb8/0x250 __x64_sys_exit_group+0x3a/0x50 x64_sys_call+0xfec/0x14f0 do_syscall_64+0x93/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e

References

NVD — CVE-2025-21756 NVD

https://nvd.nist.gov/vuln/detail/CVE-2025-21756

cert-portal.siemens.com/productcert/html/ss... WEB

https://cert-portal.siemens.com/productcert/html/ssa-082556.html

cert-portal.siemens.com/productcert/html/ss... WEB

https://cert-portal.siemens.com/productcert/html/ssa-265688.html

cert-portal.siemens.com/productcert/html/ss... WEB

https://cert-portal.siemens.com/productcert/html/ssa-784472.html

git.kernel.org/stable/c/3f43540166... WEB

https://git.kernel.org/stable/c/3f43540166128951cc1be7ab1ce6b7f05c670d8b

git.kernel.org/stable/c/42b33381e5... WEB

https://git.kernel.org/stable/c/42b33381e5e1f2b967dc4fb4221ddb9aaf10d197

git.kernel.org/stable/c/645ce25aa0... WEB

https://git.kernel.org/stable/c/645ce25aa0e67895b11d89f27bb86c9d444c40f8

git.kernel.org/stable/c/b1afd40321... WEB

https://git.kernel.org/stable/c/b1afd40321f1c243cffbcf40ea7ca41aca87fa5e

git.kernel.org/stable/c/e48fcb403c... WEB

https://git.kernel.org/stable/c/e48fcb403c2d0e574c19683f09399ab4cf67809c

git.kernel.org/stable/c/e7754d5645... WEB

https://git.kernel.org/stable/c/e7754d564579a5db9c5c9f74228df5d6dd6f1173

git.kernel.org/stable/c/fcdd2242c0... WEB

https://git.kernel.org/stable/c/fcdd2242c0231032fc84e1404315c245ae56322a

Software Source Repository REPOSITORY

https://github.com/hoefler02/CVE-2025-21756/blob/main/x.c

lists.debian.org/debian-lts-announce... WEB

https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html

lists.debian.org/debian-lts-announce... WEB

https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html

Frequently Asked Questions

What is CVE-2025-21756?

CVE-2025-21756 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-416: Use After Free.

Which Software versions are affected?

Affected versions include releases prior to current release patches.

What version fixes CVE-2025-21756?

Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.

What is the CVSS score of CVE-2025-21756?

CVE-2025-21756 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-2025-21756?

CVE-2025-21756 is classified under CWE-416: Use After Free (The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.).

How can I check Maven dependencies for CVE-2025-21756?

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

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-5828-2c94-235c",
  "modified" : "2026-10-15T03:34:35Z",
  "published" : "2025-02-27T03:34:05Z",
  "aliases" : [ "CVE-2025-21756" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nvsock: Keep the binding until socket destruction\n\nPreserve sockets bindings; this includes both resulting from an explicit\nbind() and those implicitly bound through autobind during connect().\n\nPrevents socket unbinding during a transport reassignment, which fixes a\nuse-after-free:\n\n    1. vsock_create() (refcnt=1) calls vsock_insert_unbound() (refcnt=2)\n    2. transport->release() calls vsock_remove_bound() without checking if\n       sk was bound and moved to bound list (refcnt=1)\n    3. vsock_bind() assumes sk is in unbound list and before\n       __vsock_insert_bound(vsock_bound_sockets()) calls\n       __vsock_remove_bound() which does:\n           list_del_init(&vsk->bound_table); // nop\n           sock_put(&vsk->sk);               // refcnt=0\n\nBUG: KASAN: slab-use-after-free in __vsock_bind+0x62e/0x730\nRead of size 4 at addr ffff88816b46a74c by task a.out/2057\n dump_stack_lvl+0x68/0x90\n print_report+0x174/0x4f6\n kasan_report+0xb9/0x190\n __vsock_bind+0x62e/0x730\n vsock_bind+0x97/0xe0\n __sys_bind+0x154/0x1f0\n __x64_sys_bind+0x6e/0xb0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nAllocated by task 2057:\n kasan_save_stack+0x1e/0x40\n kasan_save_track+0x10/0x30\n __kasan_slab_alloc+0x85/0x90\n kmem_cache_alloc_noprof+0x131/0x450\n sk_prot_alloc+0x5b/0x220\n sk_alloc+0x2c/0x870\n __vsock_create.constprop.0+0x2e/0xb60\n vsock_create+0xe4/0x420\n __sock_create+0x241/0x650\n __sys_socket+0xf2/0x1a0\n __x64_sys_socket+0x6e/0xb0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nFreed by task 2057:\n kasan_save_stack+0x1e/0x40\n kasan_save_track+0x10/0x30\n kasan_save_free_info+0x37/0x60\n __kasan_slab_free+0x4b/0x70\n kmem_cache_free+0x1a1/0x590\n __sk_destruct+0x388/0x5a0\n __vsock_bind+0x5e1/0x730\n vsock_bind+0x97/0xe0\n __sys_bind+0x154/0x1f0\n __x64_sys_bind+0x6e/0xb0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nrefcount_t: addition on 0; use-after-free.\nWARNING: CPU: 7 PID: 2057 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150\nRIP: 0010:refcount_warn_saturate+0xce/0x150\n __vsock_bind+0x66d/0x730\n vsock_bind+0x97/0xe0\n __sys_bind+0x154/0x1f0\n __x64_sys_bind+0x6e/0xb0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nrefcount_t: underflow; use-after-free.\nWARNING: CPU: 7 PID: 2057 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150\nRIP: 0010:refcount_warn_saturate+0xee/0x150\n vsock_remove_bound+0x187/0x1e0\n __vsock_release+0x383/0x4a0\n vsock_release+0x90/0x120\n __sock_release+0xa3/0x250\n sock_close+0x14/0x20\n __fput+0x359/0xa80\n task_work_run+0x107/0x1d0\n do_exit+0x847/0x2560\n do_group_exit+0xb8/0x250\n __x64_sys_exit_group+0x3a/0x50\n x64_sys_call+0xfec/0x14f0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e",
  "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-2025-21756"
  }, {
    "type" : "WEB",
    "url" : "https://cert-portal.siemens.com/productcert/html/ssa-082556.html"
  }, {
    "type" : "WEB",
    "url" : "https://cert-portal.siemens.com/productcert/html/ssa-265688.html"
  }, {
    "type" : "WEB",
    "url" : "https://cert-portal.siemens.com/productcert/html/ssa-784472.html"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/3f43540166128951cc1be7ab1ce6b7f05c670d8b"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/42b33381e5e1f2b967dc4fb4221ddb9aaf10d197"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/645ce25aa0e67895b11d89f27bb86c9d444c40f8"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/b1afd40321f1c243cffbcf40ea7ca41aca87fa5e"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/e48fcb403c2d0e574c19683f09399ab4cf67809c"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/e7754d564579a5db9c5c9f74228df5d6dd6f1173"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/fcdd2242c0231032fc84e1404315c245ae56322a"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/hoefler02/CVE-2025-21756/blob/main/x.c"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-416" ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2025-02-27T03:15:16Z"
  }
}

CVSS V3

7.8 HIGH

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)

Vector String

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Advisory Metadata

Source ID: GHSA-5828-2c94-235c
Schema Version: 1.4.0
Published: 2025-02-27 03:34
Last Modified: 2026-10-15 03:34
Database Record File: advisories/unreviewed/2025/02/GHSA-5828-2c94-235c/GHSA-5828-2c94-235c.json