CVE-2026-31786

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Source
https://cve.org/CVERecord?id=CVE-2026-31786
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-31786.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2026-31786
Downstream
Related
Published
2026-04-30T10:31:28.293Z
Modified
2026-06-18T03:56:13.493639191Z
Severity
  • 7.8 (High) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
Summary
Buffer overflow in drivers/xen/sys-hypervisor.c
Details

In the Linux kernel, the following vulnerability has been resolved:

Buffer overflow in drivers/xen/sys-hypervisor.c

The build id returned by HYPERVISORxenversion(XENVERbuildid) 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

Database specific 
{
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31786.json"
}
References

Affected packages

Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Affected ranges

Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
84b7625728ea311ea35bdaa0eded53c1c56baeaa
Fixed
e3af585e1728c917682b6a3de9a69b41fb9194d4
Fixed
8288d031a01dbacfde3fc643f7be3d23504de64d
Fixed
f458ba102da97fafca106327086fc95f3fc764cb
Fixed
4b4defd2fce3f966c25adabf46644a85558f1169
Fixed
5c5ff7c7bd15bb536f44b10b3fb5b8408f344d0a
Fixed
d5f59216650c51e5e3fcb7517c825bc8047f60ef
Fixed
52cecff98bda2c51eed1c6ce9d21c5d6268fb19d
Fixed
27fdbab4221b375de54bf91919798d88520c6e28

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-31786.json"

Linux / Kernel

Package

Name
Kernel

Affected ranges

Type
ECOSYSTEM
Events
Introduced
4.13.0
Fixed
5.10.254
Type
ECOSYSTEM
Events
Introduced
5.11.0
Fixed
5.15.204
Type
ECOSYSTEM
Events
Introduced
5.16.0
Fixed
6.1.170
Type
ECOSYSTEM
Events
Introduced
6.2.0
Fixed
6.6.137
Type
ECOSYSTEM
Events
Introduced
6.7.0
Fixed
6.12.85
Type
ECOSYSTEM
Events
Introduced
6.13.0
Fixed
6.18.26
Type
ECOSYSTEM
Events
Introduced
6.19.0
Fixed
7.0.3

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-31786.json"