Answer in brief
CVE-2026-31786 records a High severity (CVSS 7.8) vulnerability in Buffer overflow in drivers/xen/sys-hypervisor.c. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=84b7625728ea311ea35bdaa0eded53c1c56baeaa <e3af585e1728c917682b6a3de9a69b41fb9194d4 || >=84b7625728ea311ea35bdaa0eded53c1c56baeaa <8288d031a01dbacfde3fc643f7be3d23504de64d || >=84b7625728ea311ea35bdaa0eded53c1c56baeaa <f458ba102da97fafca106327086fc95f3fc764cb || >=84b7625728ea311ea35bdaa0eded53c1c56baeaa <4b4defd2fce3f966c25adabf46644a85558f1169 || >=84b7625728ea311ea35bdaa0eded53c1c56baeaa <5c5ff7c7bd15bb536f44b10b3fb5b8408f344d0a || >=84b7625728ea311ea35bdaa0eded53c1c56baeaa <d5f59216650c51e5e3fcb7517c825bc8047f60ef || >=84b7625728ea311ea35bdaa0eded53c1c56baeaa <52cecff98bda2c51eed1c6ce9d21c5d6268fb19d || >=84b7625728ea311ea35bdaa0eded53c1c56baeaa <27fdbab4221b375de54bf91919798d88520c6e28 | e3af585e1728c917682b6a3de9a69b41fb9194d4, 8288d031a01dbacfde3fc643f7be3d23504de64d, f458ba102da97fafca106327086fc95f3fc764cb, 4b4defd2fce3f966c25adabf46644a85558f1169, 5c5ff7c7bd15bb536f44b10b3fb5b8408f344d0a, d5f59216650c51e5e3fcb7517c825bc8047f60ef, 52cecff98bda2c51eed1c6ce9d21c5d6268fb19d, 27fdbab4221b375de54bf91919798d88520c6e28 |
| Linux/Linuxgeneric | 4.13 | Not reported |
Published upstream
Apr 30, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 16, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 16, 2026
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
Quoted source text, attributed separately from HOL analysis.