CVE-2025-21976
Full vulnerability record from the local CVENow database.
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.
Severity
MEDIUM
CVSS score
5.5
(v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2025-04-01 16:15:28.973000
Last modified
2026-10-21 13:18:03.923000
View original CVE JSON
{
"id": "CVE-2025-21976",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2025-04-01T16:15:28.973",
"lastModified": "2026-10-21T13:18:03.923",
"vulnStatus": "Modified",
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{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfbdev: hyperv_fb: Allow graceful removal of framebuffer\n\nWhen a Hyper-V framebuffer device is unbind, hyperv_fb driver tries to\nrelease the framebuffer forcefully. If this framebuffer is in use it\nproduce the following WARN and hence this framebuffer is never released.\n\n[ 44.111220] WARNING: CPU: 35 PID: 1882 at drivers/video/fbdev/core/fb_info.c:70 framebuffer_release+0x2c/0x40\n< snip >\n[ 44.111289] Call Trace:\n[ 44.111290] <TASK>\n[ 44.111291] ? show_regs+0x6c/0x80\n[ 44.111295] ? __warn+0x8d/0x150\n[ 44.111298] ? framebuffer_release+0x2c/0x40\n[ 44.111300] ? report_bug+0x182/0x1b0\n[ 44.111303] ? handle_bug+0x6e/0xb0\n[ 44.111306] ? exc_invalid_op+0x18/0x80\n[ 44.111308] ? asm_exc_invalid_op+0x1b/0x20\n[ 44.111311] ? framebuffer_release+0x2c/0x40\n[ 44.111313] ? hvfb_remove+0x86/0xa0 [hyperv_fb]\n[ 44.111315] vmbus_remove+0x24/0x40 [hv_vmbus]\n[ 44.111323] device_remove+0x40/0x80\n[ 44.111325] device_release_driver_internal+0x20b/0x270\n[ 44.111327] ? bus_find_device+0xb3/0xf0\n\nFix this by moving the release of framebuffer and assosiated memory\nto fb_ops.fb_destroy function, so that framebuffer framework handles\nit gracefully.\n\nWhile we fix this, also replace manual registrations/unregistration of\nframebuffer with devm_register_framebuffer."
},
{
"lang": "es",
"value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: fbdev: hyperv_fb: Permite la eliminación ordenada del framebuffer. Cuando se desvincula un dispositivo framebuffer de Hyper-V, el controlador hyperv_fb intenta liberarlo forzosamente. Si este framebuffer está en uso, genera la siguiente advertencia y, por lo tanto, nunca se libera. [44.111220] ADVERTENCIA: CPU: 35 PID: 1882 en drivers/video/fbdev/core/fb_info.c:70 framebuffer_release+0x2c/0x40 < snip > [44.111289] Rastreo de llamadas: [ 44.111290] [ 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. Solucione esto trasladando la liberación del framebuffer y la memoria asociada a la función fb_ops.fb_destroy, para que el framework del framebuffer lo gestione correctamente. Mientras lo solucionamos, también reemplace el registro/desregistro manual del framebuffer con devm_register_framebuffer."
}
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