CVE-2024-50102

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Source
https://nvd.nist.gov/vuln/detail/CVE-2024-50102
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2024-50102.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2024-50102
Downstream
Related
Published
2024-11-05T17:10:37Z
Modified
2025-10-17T15:15:51.295963Z
Severity
  • 5.5 (Medium) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N CVSS Calculator
Summary
x86: fix user address masking non-canonical speculation issue
Details

In the Linux kernel, the following vulnerability has been resolved:

x86: fix user address masking non-canonical speculation issue

It turns out that AMD has a "Meltdown Lite(tm)" issue with non-canonical accesses in kernel space. And so using just the high bit to decide whether an access is in user space or kernel space ends up with the good old "leak speculative data" if you have the right gadget using the result:

CVE-2020-12965 “Transient Execution of Non-Canonical Accesses“

Now, the kernel surrounds the access with a STAC/CLAC pair, and those instructions end up serializing execution on older Zen architectures, which closes the speculation window.

But that was true only up until Zen 5, which renames the AC bit [1]. That improves performance of STAC/CLAC a lot, but also means that the speculation window is now open.

Note that this affects not just the new address masking, but also the regular validuseraddress() check used by accessok(), and the asm version of the sign bit check in the getuser() helpers.

It does not affect putuser() or clearuser() variants, since there's no speculative result to be used in a gadget for those operations.

References

Affected packages

Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Affected ranges

Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
b19b74bc99b1501a550f4448d04d59b946dc617a
Fixed
291313693677a345d4f50aae3c68e28b469f601e
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
b19b74bc99b1501a550f4448d04d59b946dc617a
Fixed
86e6b1547b3d013bc392adf775b89318441403c2

Affected versions

v6.*

v6.10
v6.10-rc1
v6.10-rc2
v6.10-rc3
v6.10-rc4
v6.10-rc5
v6.10-rc6
v6.10-rc7
v6.11
v6.11-rc1
v6.11-rc2
v6.11-rc3
v6.11-rc4
v6.11-rc5
v6.11-rc6
v6.11-rc7
v6.11.1
v6.11.2
v6.11.3
v6.11.4
v6.11.5
v6.12-rc1
v6.12-rc2
v6.12-rc3
v6.12-rc4
v6.3
v6.3-rc3
v6.3-rc4
v6.3-rc5
v6.3-rc6
v6.3-rc7
v6.4
v6.4-rc1
v6.4-rc2
v6.4-rc3
v6.4-rc4
v6.4-rc5
v6.4-rc6
v6.4-rc7
v6.5
v6.5-rc1
v6.5-rc2
v6.5-rc3
v6.5-rc4
v6.5-rc5
v6.5-rc6
v6.5-rc7
v6.6
v6.6-rc1
v6.6-rc2
v6.6-rc3
v6.6-rc4
v6.6-rc5
v6.6-rc6
v6.6-rc7
v6.7
v6.7-rc1
v6.7-rc2
v6.7-rc3
v6.7-rc4
v6.7-rc5
v6.7-rc6
v6.7-rc7
v6.7-rc8
v6.8
v6.8-rc1
v6.8-rc2
v6.8-rc3
v6.8-rc4
v6.8-rc5
v6.8-rc6
v6.8-rc7
v6.9
v6.9-rc1
v6.9-rc2
v6.9-rc3
v6.9-rc4
v6.9-rc5
v6.9-rc6
v6.9-rc7

Database specific

vanir_signatures

[
    {
        "deprecated": false,
        "signature_version": "v1",
        "signature_type": "Line",
        "id": "CVE-2024-50102-6947ef55",
        "digest": {
            "line_hashes": [
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                "306528877591348781651836693115989124621",
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                "91087194636320479293431123633165652647",
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            ],
            "threshold": 0.9
        },
        "source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@86e6b1547b3d013bc392adf775b89318441403c2",
        "target": {
            "file": "arch/x86/include/asm/uaccess_64.h"
        }
    },
    {
        "deprecated": false,
        "signature_version": "v1",
        "signature_type": "Line",
        "id": "CVE-2024-50102-6ad2480f",
        "digest": {
            "line_hashes": [
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                "319696244089875446074420433513794616720",
                "85819510941787433233099107669981704342",
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            ],
            "threshold": 0.9
        },
        "source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@86e6b1547b3d013bc392adf775b89318441403c2",
        "target": {
            "file": "arch/x86/kernel/cpu/common.c"
        }
    },
    {
        "deprecated": false,
        "signature_version": "v1",
        "signature_type": "Line",
        "id": "CVE-2024-50102-a048b95a",
        "digest": {
            "line_hashes": [
                "262099056151233910369436337623650813897",
                "319696244089875446074420433513794616720",
                "85819510941787433233099107669981704342",
                "262577093884496016363596385927894239676",
                "249805904087874981031572866377618073661",
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                "228471459057573308842478952216873641602",
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            ],
            "threshold": 0.9
        },
        "source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@291313693677a345d4f50aae3c68e28b469f601e",
        "target": {
            "file": "arch/x86/kernel/cpu/common.c"
        }
    },
    {
        "deprecated": false,
        "signature_version": "v1",
        "signature_type": "Function",
        "id": "CVE-2024-50102-c331355b",
        "digest": {
            "length": 767.0,
            "function_hash": "141017255577455620157563035273586195390"
        },
        "source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@86e6b1547b3d013bc392adf775b89318441403c2",
        "target": {
            "function": "arch_cpu_finalize_init",
            "file": "arch/x86/kernel/cpu/common.c"
        }
    },
    {
        "deprecated": false,
        "signature_version": "v1",
        "signature_type": "Line",
        "id": "CVE-2024-50102-c6c47f45",
        "digest": {
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                "306528877591348781651836693115989124621",
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            "threshold": 0.9
        },
        "source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@291313693677a345d4f50aae3c68e28b469f601e",
        "target": {
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        }
    },
    {
        "deprecated": false,
        "signature_version": "v1",
        "signature_type": "Function",
        "id": "CVE-2024-50102-f0554e64",
        "digest": {
            "length": 767.0,
            "function_hash": "141017255577455620157563035273586195390"
        },
        "source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@291313693677a345d4f50aae3c68e28b469f601e",
        "target": {
            "function": "arch_cpu_finalize_init",
            "file": "arch/x86/kernel/cpu/common.c"
        }
    }
]

Linux / Kernel

Package

Name
Kernel

Affected ranges

Type
ECOSYSTEM
Events
Introduced
6.4.0
Fixed
6.11.6