FKIE_CVE-2025-68296
Vulnerability from fkie_nvd - Published: 2025-12-16 16:16 - Updated: 2026-10-14 16:10
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
drm, fbcon, vga_switcheroo: Avoid race condition in fbcon setup
Protect vga_switcheroo_client_fb_set() with console lock. Avoids OOB
access in fbcon_remap_all(). Without holding the console lock the call
races with switching outputs.
VGA switcheroo calls fbcon_remap_all() when switching clients. The fbcon
function uses struct fb_info.node, which is set by register_framebuffer().
As the fb-helper code currently sets up VGA switcheroo before registering
the framebuffer, the value of node is -1 and therefore not a legal value.
For example, fbcon uses the value within set_con2fb_map() [1] as an index
into an array.
Moving vga_switcheroo_client_fb_set() after register_framebuffer() can
result in VGA switching that does not switch fbcon correctly.
Therefore move vga_switcheroo_client_fb_set() under fbcon_fb_registered(),
which already holds the console lock. Fbdev calls fbcon_fb_registered()
from within register_framebuffer(). Serializes the helper with VGA
switcheroo's call to fbcon_remap_all().
Although vga_switcheroo_client_fb_set() takes an instance of struct fb_info
as parameter, it really only needs the contained fbcon state. Moving the
call to fbcon initialization is therefore cleaner than before. Only amdgpu,
i915, nouveau and radeon support vga_switcheroo. For all other drivers,
this change does nothing.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/gpu/drm/drm_fb_helper.c",
"drivers/video/fbdev/core/fbcon.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "711ebd961190def4c69ea24b2f0be75e995af24a",
"status": "affected",
"version": "6a9ee8af344e3bd7dbd61e67037096cdf7f83289",
"versionType": "git"
},
{
"lessThan": "482330f8261b4bea8146d9bd69c1199e5dfcbb5c",
"status": "affected",
"version": "6a9ee8af344e3bd7dbd61e67037096cdf7f83289",
"versionType": "git"
},
{
"lessThan": "05814c389b53d2f3a0b9eeb90ba7a05ba77c4c2a",
"status": "affected",
"version": "6a9ee8af344e3bd7dbd61e67037096cdf7f83289",
"versionType": "git"
},
{
"lessThan": "eb76d0f5553575599561010f24c277cc5b31d003",
"status": "affected",
"version": "6a9ee8af344e3bd7dbd61e67037096cdf7f83289",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"drivers/gpu/drm/drm_fb_helper.c",
"drivers/video/fbdev/core/fbcon.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.34"
},
{
"lessThan": "2.6.34",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.143",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.61",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.17.*",
"status": "unaffected",
"version": "6.17.11",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "6.18",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm, fbcon, vga_switcheroo: Avoid race condition in fbcon setup\n\nProtect vga_switcheroo_client_fb_set() with console lock. Avoids OOB\naccess in fbcon_remap_all(). Without holding the console lock the call\nraces with switching outputs.\n\nVGA switcheroo calls fbcon_remap_all() when switching clients. The fbcon\nfunction uses struct fb_info.node, which is set by register_framebuffer().\nAs the fb-helper code currently sets up VGA switcheroo before registering\nthe framebuffer, the value of node is -1 and therefore not a legal value.\nFor example, fbcon uses the value within set_con2fb_map() [1] as an index\ninto an array.\n\nMoving vga_switcheroo_client_fb_set() after register_framebuffer() can\nresult in VGA switching that does not switch fbcon correctly.\n\nTherefore move vga_switcheroo_client_fb_set() under fbcon_fb_registered(),\nwhich already holds the console lock. Fbdev calls fbcon_fb_registered()\nfrom within register_framebuffer(). Serializes the helper with VGA\nswitcheroo\u0027s call to fbcon_remap_all().\n\nAlthough vga_switcheroo_client_fb_set() takes an instance of struct fb_info\nas parameter, it really only needs the contained fbcon state. Moving the\ncall to fbcon initialization is therefore cleaner than before. Only amdgpu,\ni915, nouveau and radeon support vga_switcheroo. For all other drivers,\nthis change does nothing."
},
{
"lang": "es",
"value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\ndrm, fbcon, vga_switcheroo: Evitar condici\u00f3n de carrera en la configuraci\u00f3n de fbcon\n\nProteger vga_switcheroo_client_fb_set() con el bloqueo de consola. Evita el acceso OOB en fbcon_remap_all(). Sin mantener el bloqueo de consola, la llamada entra en condici\u00f3n de carrera con el cambio de salidas.\n\nVGA switcheroo llama a fbcon_remap_all() al cambiar de clientes. La funci\u00f3n fbcon usa struct fb_info.node, que es establecido por register_framebuffer(). Como el c\u00f3digo del asistente de fb actualmente configura VGA switcheroo antes de registrar el framebuffer, el valor de node es -1 y por lo tanto no es un valor legal. Por ejemplo, fbcon usa el valor dentro de set_con2fb_map() [1] como un \u00edndice en un array.\n\nMover vga_switcheroo_client_fb_set() despu\u00e9s de register_framebuffer() puede resultar en un cambio de VGA que no cambia fbcon correctamente.\n\nPor lo tanto, mover vga_switcheroo_client_fb_set() bajo fbcon_fb_registered(), que ya mantiene el bloqueo de consola. Fbdev llama a fbcon_fb_registered() desde dentro de register_framebuffer(). Serializa el asistente con la llamada de VGA switcheroo a fbcon_remap_all().\n\nAunque vga_switcheroo_client_fb_set() toma una instancia de struct fb_info como par\u00e1metro, realmente solo necesita el estado fbcon contenido. Mover la llamada a la inicializaci\u00f3n de fbcon es por lo tanto m\u00e1s limpio que antes. Solo amdgpu, i915, nouveau y radeon soportan vga_switcheroo. Para todos los dem\u00e1s controladores, este cambio no hace nada."
}
],
"id": "CVE-2025-68296",
"lastModified": "2026-10-14T16:10:00.250",
"metrics": {},
"published": "2025-12-16T16:16:08.540",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/05814c389b53d2f3a0b9eeb90ba7a05ba77c4c2a"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/482330f8261b4bea8146d9bd69c1199e5dfcbb5c"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/711ebd961190def4c69ea24b2f0be75e995af24a"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/eb76d0f5553575599561010f24c277cc5b31d003"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Deferred"
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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