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CVE-2025-21976

fbdev: hyperv_fb: Allow graceful removal of framebuffer

MEDIUM
5.5
CVSS Score
Published: April 1, 2025 at 03:47 PM UTC
Updated: October 21, 2026 at 01:18 PM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

Description

In the Linux kernel, the following vulnerability has been resolved: fbdev: hyperv_fb: Allow graceful removal of framebuffer When a Hyper-V framebuffer device is unbind, hyperv_fb driver tries to release the framebuffer forcefully. If this framebuffer is in use it produce the following WARN and hence this framebuffer is never released. [ 44.111220] WARNING: CPU: 35 PID: 1882 at drivers/video/fbdev/core/fb_info.c:70 framebuffer_release+0x2c/0x40 < snip > [ 44.111289] Call Trace: [ 44.111290] <TASK> [ 44.111291] ? show_regs+0x6c/0x80 [ 44.111295] ? __warn+0x8d/0x150 [ 44.111298] ? framebuffer_release+0x2c/0x40 [ 44.111300] ? report_bug+0x182/0x1b0 [ 44.111303] ? handle_bug+0x6e/0xb0 [ 44.111306] ? exc_invalid_op+0x18/0x80 [ 44.111308] ? asm_exc_invalid_op+0x1b/0x20 [ 44.111311] ? framebuffer_release+0x2c/0x40 [ 44.111313] ? hvfb_remove+0x86/0xa0 [hyperv_fb] [ 44.111315] vmbus_remove+0x24/0x40 [hv_vmbus] [ 44.111323] device_remove+0x40/0x80 [ 44.111325] device_release_driver_internal+0x20b/0x270 [ 44.111327] ? bus_find_device+0xb3/0xf0 Fix this by moving the release of framebuffer and assosiated memory to fb_ops.fb_destroy function, so that framebuffer framework handles it gracefully. While we fix this, also replace manual registrations/unregistration of framebuffer with devm_register_framebuffer.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Linux Kernel· Linux
95%
3.10 ≤ v < 6.12.206.13 ≤ v < 6.13.86.146.14 rc16.14 rc26.14 rc36.14 rc46.14 rc56.14 rc668a2d20b79b105f02dcbc52c211d7e62f98996b7
Vendor states this is fixed in 4545e2aa121aea304d33903099c03e29ed4fe50a (fixed)
Vendor states this is fixed in a7b583dc99c6cf4a96877017be1d08247e1ef2c7 (fixed)
Vendor states this is fixed in ea2f45ab0e53b255f72c85ccd99e2b394fc5fceb (fixed)
Vendor states this is fixed in 3.10 (unaffected)
Vendor states this is fixed in 6.12.20 (unaffected)
Vendor states this is fixed in 6.13.8 (unaffected)
Vendor states this is fixed in 6.14 (unaffected)
Vendor states this is fixed in 6.6.160 (unaffected)

References (4)

Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/4545e2aa121aea304d33903099c03e29ed4fe50a
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/a7b583dc99c6cf4a96877017be1d08247e1ef2c7
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/ea2f45ab0e53b255f72c85ccd99e2b394fc5fceb
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/b1a86a5ab0d44160534f495a3630646092d98e27

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.5MEDIUM[email protected]
Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
NVD-CWE-noinfo

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