CVE-2025-8860
Qemu-kvm: uefi-vars: information disclosure vulnerability in uefi_vars_write callback
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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
3.3
Qemu-kvm: uefi-vars: information disclosure vulnerability in uefi_vars_write callback
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.
- Record
CVE-2025-8860- CVSS 3.1
- 3.3 Low
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-212
- Updated
- 2026-11-02
EUVDEUVD-2025-207826
3.3
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.
- Record
EUVD-2025-207826- CVSS 3.1
- 3.3 Low
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-xrj7-v4x4-74hr
3.3
A flaw was found in QEMU in the uefi-vars virtual device. When the guest writes to register...
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.
- Record
GHSA-xrj7-v4x4-74hr- CVSS 3.1
- 3.3 Low
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-212
- Updated
- 2026-11-02
NVD
3.3
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.
- Record
CVE-2025-8860- CVSS 3.1
- 3.3 Low
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-212
- Updated
- 2026-11-02
OSV
3.3
Qemu-kvm: uefi-vars: information disclosure vulnerability in uefi_vars_write callback
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.
- Record
CVE-2025-8860- CVSS 3.1
- 3.3 Low
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-212
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2025-8860
3.3
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.
- Record
DEBIAN-CVE-2025-8860- CVSS 3.1
- 3.3 Low
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Updated
- 2026-11-02
OSVUBUNTU-CVE-2025-8860 No score
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.
- Record
UBUNTU-CVE-2025-8860- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
qemuDebian:13 |
before 1:10.0.3+ds-4, plus listed versions 1:10.0.2+ds-21:10.0.2+ds-2+deb13u11:10.0.2+ds-2+deb13u1~bpo12+11:10.0.3+ds-0+deb13u11:10.0.3+ds-11:10.0.3+ds-21:10.0.3+ds-3 |
1:10.0.3+ds-4 |
qemuDebian:14 |
before 1:10.0.3+ds-4, plus listed versions 1:10.0.2+ds-21:10.0.3+ds-11:10.0.3+ds-21:10.0.3+ds-3 |
1:10.0.3+ds-4 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected | ||
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-8860 is a low vulnerability (CVSS 3.3) in Red Hat Enterprise Linux 10, published August 20, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.17%, the 6th percentile. Fixed in qemu 1:10.0.3+ds-4.