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CVE-2025-39716 – parisc: Revise __get_user() to probe user read access

The following table lists the changes that have been made to the
CVE-2025-39716 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution
of a vulnerability, and for identifying the most recent changes that may
impact the vulnerability’s severity, exploitability, or other characteristics.

  • New CVE Received
    by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Sep. 05, 2025

    Action Type Old Value New Value
    Added Description In the Linux kernel, the following vulnerability has been resolved:

    parisc: Revise __get_user() to probe user read access

    Because of the way read access support is implemented, read access
    interruptions are only triggered at privilege levels 2 and 3. The
    kernel executes at privilege level 0, so __get_user() never triggers
    a read access interruption (code 26). Thus, it is currently possible
    for user code to access a read protected address via a system call.

    Fix this by probing read access rights at privilege level 3 (PRIV_USER)
    and setting __gu_err to -EFAULT (-14) if access isn’t allowed.

    Note the cmpiclr instruction does a 32-bit compare because COND macro
    doesn’t work inside asm.
    Added Reference https://git.kernel.org/stable/c/28a9b71671fb4a2993ef85b8ef6f117ea63894fe
    Added Reference https://git.kernel.org/stable/c/4c981077255acc2ed5b3df6e8dd0125c81b626a9
    Added Reference https://git.kernel.org/stable/c/741b163e440683195b8fd4fc8495fcd0105c6ab7
    Added Reference https://git.kernel.org/stable/c/89f686a0fb6e473a876a9a60a13aec67a62b9a7e
    Added Reference https://git.kernel.org/stable/c/f410ef9a032caf98117256b22139c31342d7bb06
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