# CVE-2026-74753: perf: Reject exited events as group leaders

> A use-after-free vulnerability in the Linux kernel perf subsystem allows attackers to execute arbitrary code or escalate privileges via crafted event groups.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 26 Aug 2026
- **Updated:** 16 Oct 2026
- **Also known as:** AZL-97778, BELL-CVE-2026-74753, DEBIAN-CVE-2026-74753, GHSA-4mpw-g9mg-jrm7, UBUNTU-CVE-2026-74753

## What is CVE-2026-74753?

CVE-2026-74753 is a high-severity use after free vulnerability in Linux, published on 26 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

perf: Reject exited events as group leaders

perf_event_remove_on_exec() sets remove-on-exec events to the EXIT state
and detaches their group relationships.  The event's file descriptor can
remain open, however, and perf_event_open() currently accepts that event
as a group leader because its early validation rejects only REVOKED and
DEAD events.

A new sibling can consequently be linked to the detached leader.  When
the leader is closed, perf_group_detach() observes that its
PERF_ATTACH_GROUP bit is already clear and skips the new sibling.  The
sibling then retains a group_leader pointer to the freed event.

Reject group leaders in the EXIT state.  Perform the check while holding
the shared context mutex so that an exec in the target task cannot detach
the leader between validation and group attachment.

[peterz: make the earlier test fully consistent]

## Which versions are affected by CVE-2026-74753?


## How do I fix CVE-2026-74753?

Apply the vendor's patch.

## Is CVE-2026-74753 being exploited?

There is no known exploitation of CVE-2026-74753 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74753 and fix it if it is affected.

What it is: CVE-2026-74753 is a high-severity use after free vulnerability in Linux, published on 26 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-74753 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-74753/ (Markdown: https://insights.sbomify.com/CVE-2026-74753/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74753
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74753
- OSV: https://osv.dev/vulnerability/CVE-2026-74753

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74753/
Summaries are generated and may contain mistakes; the official description above is the record.