DEBIAN-CVE-2026-80876

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    DEBIAN-CVE-2026-80876

    Published: 4 Sept 2026Last Modified: 14 Sept 2026
    Upstream:
    CVE-2026-80876

    Summary:

    Details: In the Linux kernel, the following vulnerability has been resolved: ring-buffer: Fix event length with forced 8-byte alignment When RB_FORCE_8BYTE_ALIGNMENT is true, rb_calculate_event_length() reserves the space of event->array[0] for placing the data length and rb_update_event() stores the data length in event->array[0] accordingly. As a result the whole event length will add extra 4 bytes for sizeof(event.array[0]) unconditionally. But ring_buffer_event_length() only subtracts the sizeof(event->array[0]) for events larger than RB_MAX_SMALL_DATA + sizeof(event->array[0]). As a result, small events on architectures with RB_FORCE_8BYTE_ALIGNMENT=true report a data length that is 4 bytes larger than expected. To fix it, add the RB_FORCE_8BYTE_ALIGNMENT as a condition to subtract the size of that length field whenever RB_FORCE_8BYTE_ALIGNMENT is true. This issue is observed in a riscv64 kernel with CONFIG_HAVE_64BIT_ALIGNED_ACCESS set to y, when we run ftrace selftest trace_marker_raw.tc, we get the weird log: for cases where the id is 1..100, the number of data field is 8*N, but once id exceeds 100, the number of data field becomes 8*N+4: # 1 buf: 58 00 00 00 80 5e d1 63 (number of data field is 8*1) ... # a buf: 58 ... (number of data field is 8*2) ... # 64 buf: 58 ... (number of data field is 8*13) # 65 buf: 58 ... (number of data field is 8*13+4) After applying this change, the number of data field keeps being 8*N+4 consistently.

    References: https://security-tracker.debian.org/tracker/CVE-2026-80876

    Affected packages

    Package

    Name: linux

    Purl: pkg:deb/debian/linux?arch=source&distro=bookworm

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -6.1.180-1

    Affected versions

    6.1.106-1
    6.1.106-2
    6.1.106-3
    6.1.112-1
    6.1.115-1
    6.1.119-1
    6.1.123-1
    6.1.124-1
    6.1.128-1
    6.1.129-1
    6.1.133-1
    6.1.135-1
    6.1.137-1
    6.1.139-1
    6.1.140-1
    6.1.147-1
    6.1.148-1
    6.1.153-1
    6.1.158-1
    6.1.159-1
    6.1.162-1
    6.1.164-1
    6.1.170-1
    6.1.170-2
    6.1.170-3
    6.1.172-1
    6.1.174-1
    6.1.176-1
    6.1.177-1
    6.1.27-1
    6.1.37-1
    6.1.38-1
    6.1.38-2
    6.1.38-2~bpo11+1
    6.1.38-3
    6.1.38-4
    6.1.38-4~bpo11+1
    6.1.52-1
    6.1.55-1
    6.1.55-1~bpo11+1
    6.1.64-1
    6.1.66-1
    6.1.67-1
    6.1.69-1
    6.1.69-1~bpo11+1
    6.1.76-1
    6.1.76-1~bpo11+1
    6.1.82-1
    6.1.85-1
    6.1.90-1
    6.1.90-1~bpo11+1
    6.1.94-1
    6.1.94-1~bpo11+1
    6.1.98-1
    6.1.99-1

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
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