CVE-2026-31786 (GCVE-0-2026-31786)
Vulnerability from cvelistv5
Published
2026-04-30 10:31
Modified
2026-05-04 07:46
Severity ?
VLAI Severity ?
EPSS score ?
Summary
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
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 84b7625728ea311ea35bdaa0eded53c1c56baeaa Version: 84b7625728ea311ea35bdaa0eded53c1c56baeaa Version: 84b7625728ea311ea35bdaa0eded53c1c56baeaa Version: 84b7625728ea311ea35bdaa0eded53c1c56baeaa Version: 84b7625728ea311ea35bdaa0eded53c1c56baeaa Version: 84b7625728ea311ea35bdaa0eded53c1c56baeaa Version: 84b7625728ea311ea35bdaa0eded53c1c56baeaa Version: 84b7625728ea311ea35bdaa0eded53c1c56baeaa |
||
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"descriptions": [
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBuffer overflow in drivers/xen/sys-hypervisor.c\n\nThe build id returned by HYPERVISOR_xen_version(XENVER_build_id) is\nneither NUL terminated nor a string.\n\nThe first causes a buffer overflow as sprintf in buildid_show will\nread and copy till it finds a NUL.\n\n00000000 f4 91 51 f4 dd 38 9e 9d 65 47 52 eb 10 71 db 50 |..Q..8..eGR..q.P|\n00000010 b9 a8 01 42 6f 2e 32 |...Bo.2|\n00000017\n\nSo use a memcpy instead of sprintf to have the correct value:\n\n00000000 f4 91 51 f4 dd 00 9e 9d 65 47 52 eb 10 71 db 50 |..Q.....eGR..q.P|\n00000010 b9 a8 01 42 |...B|\n00000014\n\n(the above have a hack to embed a zero inside and check it\u0027s\nreturned correctly).\n\nThis is XSA-485 / CVE-2026-31786"
}
],
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"url": "https://git.kernel.org/stable/c/4b4defd2fce3f966c25adabf46644a85558f1169"
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"datePublished": "2026-04-30T10:31:28.293Z",
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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