CVE-2026-31786

HIGH EPSS 9.6%
Published Apr 30, 20262mo ago · Modified Jun 17, 20261w ago
7.8 CVSS 3.1
High
Find Similar
Published Apr 30, 2026 2mo ago
Last Modified Jun 17, 2026 1w ago

Description

In the Linux kernel, the following vulnerability has been resolved: Buffer overflow in drivers/xen/sys-hypervisor.c The build id returned by HYPERVISOR_xen_version(XENVER_build_id) is neither NUL terminated nor a string. The first causes a buffer overflow as sprintf in buildid_show will read and copy till it finds a NUL. 00000000 f4 91 51 f4 dd 38 9e 9d 65 47 52 eb 10 71 db 50 |..Q..8..eGR..q.P| 00000010 b9 a8 01 42 6f 2e 32 |...Bo.2| 00000017 So use a memcpy instead of sprintf to have the correct value: 00000000 f4 91 51 f4 dd 00 9e 9d 65 47 52 eb 10 71 db 50 |..Q.....eGR..q.P| 00000010 b9 a8 01 42 |...B| 00000014 (the above have a hack to embed a zero inside and check it's returned correctly). This is XSA-485 / CVE-2026-31786

CVSS Details

Base Score
7.8
Exploitability
1.8
Impact
5.9
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality High
Integrity High
Availability High

Threat Intelligence

EPSS Exploit Probability
9.6% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-787 Out-of-bounds Write Memory Safety

Affected Products 9

VendorProductVersionRange
linuxlinux_kernel*≥4.13  –  <5.10.254
linuxlinux_kernel*≥5.11  –  <5.15.204
linuxlinux_kernel*≥5.16  –  <6.1.170
linuxlinux_kernel*≥6.2  –  <6.6.137
linuxlinux_kernel*≥6.7  –  <6.12.85
linuxlinux_kernel*≥6.13  –  <6.18.26
linuxlinux_kernel*≥6.19  –  <7.0.3
linuxlinux_kernel7.1any
linuxlinux_kernel7.1any

References 10

  • openwall.com http://www.openwall.com/lists/oss-security/2026/04/28/12
    Mailing ListThird Party Advisory
  • xenbits.xen.org http://xenbits.xen.org/xsa/advisory-485.html
    Mailing ListThird Party Advisory
  • git.kernel.org https://git.kernel.org/stable/c/27fdbab4221b375de54bf91919798d88520c6e28
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/4b4defd2fce3f966c25adabf46644a85558f1169
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/52cecff98bda2c51eed1c6ce9d21c5d6268fb19d
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/5c5ff7c7bd15bb536f44b10b3fb5b8408f344d0a
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/8288d031a01dbacfde3fc643f7be3d23504de64d
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/d5f59216650c51e5e3fcb7517c825bc8047f60ef
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/e3af585e1728c917682b6a3de9a69b41fb9194d4
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/f458ba102da97fafca106327086fc95f3fc764cb
    Patch

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/27fdbab4221b375de54bf91919798d88520c6e28
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/4b4defd2fce3f966c25adabf46644a85558f1169
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/52cecff98bda2c51eed1c6ce9d21c5d6268fb19d
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/5c5ff7c7bd15bb536f44b10b3fb5b8408f344d0a
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/8288d031a01dbacfde3fc643f7be3d23504de64d
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/d5f59216650c51e5e3fcb7517c825bc8047f60ef
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/e3af585e1728c917682b6a3de9a69b41fb9194d4
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/f458ba102da97fafca106327086fc95f3fc764cb
    Patch