CVE-2026-80876 Affecting perf6.12-debuginfo package, versions <1:6.12.100-125.179.amzn2023
Threat Intelligence
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Test your applications- Snyk IDSNYK-AMZN2023-PERF612DEBUGINFO-19811428
- published15 Sept 2026
- disclosed4 Sept 2026
Introduced: 4 Sep 2026
NewCVE-2026-80876 (opens in a new tab)How to fix?
Upgrade Amazon-Linux:2023 perf6.12-debuginfo to version 1:6.12.100-125.179.amzn2023 or higher.
This issue was patched in ALAS2023-2026-2057.
NVD Description
Note: Versions mentioned in the description apply only to the upstream perf6.12-debuginfo package and not the perf6.12-debuginfo package as distributed by Amazon-Linux.
See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.
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 8N, but once id exceeds 100, the number of data field becomes 8N+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
- http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-80876
- https://git.kernel.org/stable/c/14057268e79654c3e8ea2c9b5204cb9644b2964d
- https://git.kernel.org/stable/c/24c3fa71f9947b0e1f3b954db1b769b44140192e
- https://git.kernel.org/stable/c/3a63a11897c7ba32d1be7a3fdbc48a8b01cf4992
- https://git.kernel.org/stable/c/7c9f0ccf9f04142458d2ac3d39414f4acae242f0
- https://git.kernel.org/stable/c/c37e0a4b79a6bbb96ce5ffe279d7c001e20529e0
- https://git.kernel.org/stable/c/cfada73fabe2ccc06ec77fe2ceaa088689213326
- https://git.kernel.org/stable/c/dbcb8635b1eb7603818591cf745c7b1d714f7ac6
- https://git.kernel.org/stable/c/ec5e96aee75d27779b9a860307679f13f33adb0c