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CVE-2026-31786Disclosure(linux / linux_kernel)

LOWCVSS 7.8 · HIGH

Signal is active with 1 mentions in latest observed window

Immediate actions

  • Track advisory updates for patch or workaround availability

Recommended action window: Monitor and triage in normal cycle

NVD 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

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0.0/ 10 priority

Sources & remediation

Patch / fix
Vendor / third-party advisories
Weakness type (CWE)
CWE-787

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

AVAILABLE

Momentum

STABLE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

  • linux_kernel

Threat summary

  • 2 mentions across 2 observed days
  • Momentum state: stable

What's happening

  • Technical details provided in 1 signal
  • Disclosure: 2 classified signals
  • Peaked 1d ago at 1 mentions (2026-04-29); latest day: 1
  • 2 total mentions across 2 days

Affected systems

Vendors
linux
Products
linux_kernel

1 version affected across 1 product

Deep dive

Activity timeline2 mentions / 2d
00111Mentions · 2026-04-29: 1Mentions · 2026-04-30: 1Technical Details · 2026-04-29: 104-2904-30
Signal classification1 categories
Disclosure
2100.0%
Referenced assets3 URLs
Full discourse2 posts
  • Open Source Security mailing list@oss_security
    Disclosure

    Xen 485 v2 (CVE-2026-31786): Linux kernel out of bounds read via Xen-related sysfs file https://www.openwall.com/lists/oss-security/2026/04/28/12 486 v2 (CVE-2026-23558): grant table v2 race in status page mapping https://www.openwall.com/lists/oss-security/2026/04/28/13 2/3

    Post summary

    The text announces two Xen CVEs with technical details of the vulnerabilities but provides no PoC, exploit, patch information, or evidence of active exploitation.

    11030334
    4.7K followersView on X
  • VulDB 🛡@vuldb
    Disclosure

    The severity is increased for this new vulnerability affecting Linux Kernel (CVE-2026-31786) https://vuldb.com/vuln/360294

    Post summary

    A new vulnerability, CVE-2026-31786, in the Linux Kernel has been highlighted with an increased severity rating, as referenced in a vuldb.com entry.

    0000040
    2.1K followersView on X
CPE platform detail3 entries

3 of 3 entries

PartVendorProductVersionTarget SWTarget HW
OSlinuxlinux_kernel---
OSlinuxlinux_kernel7.1--
OSlinuxlinux_kernel7.1--

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