CVE-2026-80876ring-buffer: Fix event length with forced 8-byte alignment

Description

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.

Timeline

Scores

No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Received.

EPSS (exploitation in 30 days)

0.22% · top 87% of all CVEs (14 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.

Affected products

• Linux · Linux

  • affected 2271048d1b3b0aabf83d25b29c20646dcabedc05 – < 7c9f0ccf9f04142458d2ac3d39414f4acae242f0
  • affected 2271048d1b3b0aabf83d25b29c20646dcabedc05 – < 24c3fa71f9947b0e1f3b954db1b769b44140192e
  • affected 2271048d1b3b0aabf83d25b29c20646dcabedc05 – < 14057268e79654c3e8ea2c9b5204cb9644b2964d
  • affected 2271048d1b3b0aabf83d25b29c20646dcabedc05 – < dbcb8635b1eb7603818591cf745c7b1d714f7ac6
  • affected 2271048d1b3b0aabf83d25b29c20646dcabedc05 – < cfada73fabe2ccc06ec77fe2ceaa088689213326
  • affected 2271048d1b3b0aabf83d25b29c20646dcabedc05 – < ec5e96aee75d27779b9a860307679f13f33adb0c
  • affected 2271048d1b3b0aabf83d25b29c20646dcabedc05 – < 3a63a11897c7ba32d1be7a3fdbc48a8b01cf4992
  • affected 2271048d1b3b0aabf83d25b29c20646dcabedc05 – < c37e0a4b79a6bbb96ce5ffe279d7c001e20529e0

• Linux · Linux

  • affected 2.6.34
  • unaffected < 2.6.34
  • unaffected 5.10.261 – ≤ 5.10.*
  • unaffected 5.15.212 – ≤ 5.15.*
  • unaffected 6.1.178 – ≤ 6.1.*
  • unaffected 6.6.145 – ≤ 6.6.*
  • unaffected 6.12.97 – ≤ 6.12.*
  • unaffected 6.18.40 – ≤ 6.18.*
  • unaffected 7.1.5 – ≤ 7.1.*
  • unaffected 7.2 – ≤ *

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2026-71506 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-80876](https://cveledger.app/badge/CVE-2026-80876.svg)](https://cveledger.app/cve/CVE-2026-80876)

Record last updated 6 Nov 2026, 17:05 UTC.