CVE-2026-63794: Software Security Vulnerability Vulnerability

HIGH

Advisory Identifier: GHSA-8vm9-66j5-xm27

CVSS 7.8

Published 2026-07-19

Advisory Summary

CVE-2026-63794 is a HIGH (CVSS 7.8) security vulnerability vulnerability (CWE-787: Out-of-bounds Write) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product writes data past the end, or before the beginning, of the intended buffer.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-63794 at a Glance

CVE Identifier CVE-2026-63794

GHSA Identifier GHSA-8vm9-66j5-xm27

Severity HIGH

CVSS v3.1 Base Score 7.8

CWE Classification CWE-787: Out-of-bounds Write

Affected Product Software

Package Ecosystem Maven

Published Date 2026-07-19

Last Updated 2026-07-30

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-2026-63794

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-2026-63794, 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-787: Out-of-bounds Write, where the product writes 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: KVM: SVM: Fix page overflow in sev_dbg_crypt() for ENCRYPT path In sev_dbg_crypt(), the per-iteration transfer length is bounded by the source page offset (PAGE_SIZE - s_off) but not by the destination page offset (PAGE_SIZE - d_off). When d_off > s_off, the encrypt path (__sev_dbg_encrypt_user) performs a read-modify-write using a single-page intermediate buffer (dst_tpage): 1. __sev_dbg_decrypt() expands the size to round_up(len + (d_off & 15), 16) before issuing the PSP command. If len + (d_off & 15) > PAGE_SIZE, the PSP writes beyond the end of the 4096-byte dst_tpage allocation. 2. The subsequent memcpy()/copy_from_user() into page_address(dst_tpage) + (d_off & 15) of 'len' bytes overflows by up to 15 bytes under the same condition. Trigger example: s_off = 0, d_off = 1, debug.len = PAGE_SIZE - the PSP is instructed to write round_up(4097, 16) = 4112 bytes to a 4096-byte buffer. Fix by also bounding len by (PAGE_SIZE - d_off), the same check that sev_send_update_data() already performs for its single-page guest region. ================================================================== BUG: KASAN: slab-use-after-free in sev_dbg_crypt+0x993/0xd10 [kvm_amd] Write of size 4095 at addr ff110062293bb009 by task sev_dbg_test/228214 CPU: 96 UID: 0 PID: 228214 Comm: sev_dbg_test Tainted: G U W 7.0.0-smp--5ce9b0c48211-dbg #156 PREEMPTLAZY Tainted: [U]=USER, [W]=WARN Hardware name: Google Astoria/astoria, BIOS 0.20250817.1-0 08/25/2025 Call Trace: <TASK> dump_stack_lvl+0x54/0x70 print_report+0xbc/0x260 kasan_report+0xa2/0xd0 kasan_check_range+0x25f/0x2c0 __asan_memcpy+0x40/0x70 sev_dbg_crypt+0x993/0xd10 [kvm_amd] sev_mem_enc_ioctl+0x33c/0x450 [kvm_amd] kvm_vm_ioctl+0x65d/0x6d0 [kvm] __se_sys_ioctl+0xb2/0x100 do_syscall_64+0xe8/0x870 entry_SYSCALL_64_after_hwframe+0x4b/0x53 </TASK> The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x7fe72b6a0 pfn:0x62293bb memcg:ff11000112827d82 flags: 0x1400000000000000(node=1|zone=1) raw: 1400000000000000 0000000000000000 dead000000000122 0000000000000000 raw: 00000007fe72b6a0 0000000000000000 00000001ffffffff ff11000112827d82 page dumped because: kasan: bad access detected Memory state around the buggy address: ff110062293bbf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ff110062293bbf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ff110062293bc000: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ^ ff110062293bc080: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ff110062293bc100: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ================================================================== Disabling lock debugging due to kernel taint [sean: add sample KASAN splat, Fixes, and stable@]

References

NVD — CVE-2026-63794 NVD

https://nvd.nist.gov/vuln/detail/CVE-2026-63794

git.kernel.org/stable/c/2753a097d1... WEB

https://git.kernel.org/stable/c/2753a097d1fe24c4351c608048612c74108aa89f

git.kernel.org/stable/c/64f2449841... WEB

https://git.kernel.org/stable/c/64f2449841ffc7d203183aa4c748c9c77951ecc5

git.kernel.org/stable/c/720949ed66... WEB

https://git.kernel.org/stable/c/720949ed666f34ff28ffdfe1471a5861d1e41fdf

git.kernel.org/stable/c/78ee2d5018... WEB

https://git.kernel.org/stable/c/78ee2d50185a037b3d2452a97f3dad69c3f7f389

git.kernel.org/stable/c/889c2a9c59... WEB

https://git.kernel.org/stable/c/889c2a9c59897ca912bf39df5bb92555a0a13df4

git.kernel.org/stable/c/9349b50f4b... WEB

https://git.kernel.org/stable/c/9349b50f4b11f135fe73b56cb2c2c872d8bc71d7

git.kernel.org/stable/c/e1a0fe288d... WEB

https://git.kernel.org/stable/c/e1a0fe288dee07b7da25a71e007c1ecd1080315b

git.kernel.org/stable/c/f701ae476c... WEB

https://git.kernel.org/stable/c/f701ae476cb92a3a3d8844bb39bb63b4512684c8

Frequently Asked Questions

What is CVE-2026-63794?

CVE-2026-63794 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-787: Out-of-bounds Write.

Which Software versions are affected?

Affected versions include releases prior to current release patches.

What version fixes CVE-2026-63794?

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

What is the CVSS score of CVE-2026-63794?

CVE-2026-63794 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-2026-63794?

CVE-2026-63794 is classified under CWE-787: Out-of-bounds Write (The product writes data past the end, or before the beginning, of the intended buffer.).

How can I check Maven dependencies for CVE-2026-63794?

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-8vm9-66j5-xm27",
  "modified" : "2026-07-30T18:31:12Z",
  "published" : "2026-07-19T12:30:23Z",
  "aliases" : [ "CVE-2026-63794" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SVM: Fix page overflow in sev_dbg_crypt() for ENCRYPT path\n\nIn sev_dbg_crypt(), the per-iteration transfer length is bounded by\nthe source page offset (PAGE_SIZE - s_off) but not by the destination\npage offset (PAGE_SIZE - d_off).  When d_off > s_off, the encrypt\npath (__sev_dbg_encrypt_user) performs a read-modify-write using a\nsingle-page intermediate buffer (dst_tpage):\n\n  1. __sev_dbg_decrypt() expands the size to round_up(len + (d_off & 15), 16)\n     before issuing the PSP command.  If len + (d_off & 15) > PAGE_SIZE,\n     the PSP writes beyond the end of the 4096-byte dst_tpage allocation.\n\n  2. The subsequent memcpy()/copy_from_user() into\n     page_address(dst_tpage) + (d_off & 15) of 'len' bytes overflows\n     by up to 15 bytes under the same condition.\n\nTrigger example: s_off = 0, d_off = 1, debug.len = PAGE_SIZE -\nthe PSP is instructed to write round_up(4097, 16) = 4112 bytes to\na 4096-byte buffer.\n\nFix by also bounding len by (PAGE_SIZE - d_off), the same check that\nsev_send_update_data() already performs for its single-page guest\nregion.\n\n ==================================================================\n BUG: KASAN: slab-use-after-free in sev_dbg_crypt+0x993/0xd10 [kvm_amd]\n Write of size 4095 at addr ff110062293bb009 by task sev_dbg_test/228214\n\n CPU: 96 UID: 0 PID: 228214 Comm: sev_dbg_test Tainted: G     U  W           7.0.0-smp--5ce9b0c48211-dbg #156 PREEMPTLAZY\n Tainted: [U]=USER, [W]=WARN\n Hardware name: Google Astoria/astoria, BIOS 0.20250817.1-0 08/25/2025\n Call Trace:\n  <TASK>\n  dump_stack_lvl+0x54/0x70\n  print_report+0xbc/0x260\n  kasan_report+0xa2/0xd0\n  kasan_check_range+0x25f/0x2c0\n  __asan_memcpy+0x40/0x70\n  sev_dbg_crypt+0x993/0xd10 [kvm_amd]\n  sev_mem_enc_ioctl+0x33c/0x450 [kvm_amd]\n  kvm_vm_ioctl+0x65d/0x6d0 [kvm]\n  __se_sys_ioctl+0xb2/0x100\n  do_syscall_64+0xe8/0x870\n  entry_SYSCALL_64_after_hwframe+0x4b/0x53\n  </TASK>\n\n The buggy address belongs to the physical page:\n page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x7fe72b6a0 pfn:0x62293bb\n memcg:ff11000112827d82\n flags: 0x1400000000000000(node=1|zone=1)\n raw: 1400000000000000 0000000000000000 dead000000000122 0000000000000000\n raw: 00000007fe72b6a0 0000000000000000 00000001ffffffff ff11000112827d82\n page dumped because: kasan: bad access detected\n\n Memory state around the buggy address:\n  ff110062293bbf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n  ff110062293bbf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n >ff110062293bc000: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc\n                    ^\n  ff110062293bc080: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc\n  ff110062293bc100: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc\n ==================================================================\n Disabling lock debugging due to kernel taint\n\n[sean: add sample KASAN splat, Fixes, and stable@]",
  "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-2026-63794"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/2753a097d1fe24c4351c608048612c74108aa89f"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/64f2449841ffc7d203183aa4c748c9c77951ecc5"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/720949ed666f34ff28ffdfe1471a5861d1e41fdf"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/78ee2d50185a037b3d2452a97f3dad69c3f7f389"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/889c2a9c59897ca912bf39df5bb92555a0a13df4"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/9349b50f4b11f135fe73b56cb2c2c872d8bc71d7"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/e1a0fe288dee07b7da25a71e007c1ecd1080315b"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/f701ae476cb92a3a3d8844bb39bb63b4512684c8"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-787" ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-07-19T12:16:51Z"
  }
}

CVSS V3

7.8 HIGH