What’s Vulnerable › Vulnerabilities

CVE-2025-8860: Qemu-kvm: uefi-vars: information disclosure vulnerability in uefi_vars_write callback

• Severity: low (CVSS 3.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-02-18 · updated 2026-06-17
• Weakness: CWE-212

Description

A flaw was found in QEMU in the uefi-vars virtual device. When the guest writes to register UEFI_VARS_REG_BUFFER_SIZE, the .write callback `uefi_vars_write` is invoked. The function allocates a heap buffer without zeroing the memory, leaving the buffer filled with residual data from prior allocations. When the guest later reads from register UEFI_VARS_REG_PIO_BUFFER_TRANSFER, the .read callback `uefi_vars_read` returns leftover metadata or other sensitive process memory from the previously allocated buffer, leading to an information disclosure vulnerability.

References

• https://access.redhat.com/security/cve/CVE-2025-8860
• https://bugzilla.redhat.com/show_bug.cgi?id=2387588

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