# CVE-2026-99235: tracing: Save the event file instead of the compatible histogram

CVE-2026-99235 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-99235, released November 3, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-99235
- Priority: High
- CVSS: 7.8 (Moderate)
- EPSS: 0.0012
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Nov 2, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-99235

## Description

In the Linux kernel, the following vulnerability has been resolved:  tracing: Save the event file instead of the compatible histogram  create_field_var_hist() creates a histogram on the matched event to supply a field variable, and records it on the target so it can be torn down later:  	hist_data = find_compatible_hist(target_hist_data, file); 	... 	/* Save the compatible histogram information */ 	var_hist->hist_data = hist_data;  hist_data is not the histogram it creates. It is one that was already there, whose keys the new one copies. The saved pointer has a single user, unregister_field_var_hists(), which runs when the target is removed:  	file = hist_data->field_var_hists[i]->hist_data->event_file;  find_compatible_hist() matches on keys alone, so it can pick one with no variables of its own. check_var_refs() then returns false and the user can remove it while the target still points at it:   BUG: KASAN: slab-use-after-free in event_hist_trigger_free+0x2b2/0x320  Read of size 8 at addr ffff8880093b90e0 by task init/1   Freed by task 1:   kfree+0x154/0x420   event_hist_trigger_free+0x1d5/0x320   event_hist_trigger_parse+0x35f3/0x69e0   trigger_process_regex+0x1a6/0x250  Save the event file instead. It is all the dereference ever wanted, and it does not go away when the user removes a trigger.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 13.5 (trixie) | 6.12.115-1 | [DEBIAN-CVE-2026-99235](https://patchblox.com/security/data/fix/linux/debian-cve-2026-99235.md) | Nov 3, 2026 |
| Linux | linux Debian 14 | 7.2.14-1 | [DEBIAN-CVE-2026-99235](https://patchblox.com/security/data/fix/linux/debian-cve-2026-99235.md) | Nov 3, 2026 |

---

Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.