# CVE-2026-98074: bonding: do not clear curr_active_slave prematurely when releasing all slaves

> A logic error in Linux kernel bonding driver leaks promiscuous mode on network devices during bond teardown, potentially causing resource exhaustion.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-104778, BELL-CVE-2026-98074, DEBIAN-CVE-2026-98074, GHSA-vrv6-53xj-7g2r, UBUNTU-CVE-2026-98074

## What is CVE-2026-98074?

CVE-2026-98074 is a denial of service vulnerability in Linux, published on 25 Sep 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:

bonding: do not clear curr_active_slave prematurely when releasing all slaves

When releasing all slaves during bond destruction (all == true),
__bond_release_one() unconditionally clears bond->curr_active_slave to
NULL in every iteration.

If a backup slave is released before the active slave,
bond_alb_deinit_slave() triggers rlb_teach_disabled_mac_on_primary(),
which increments the active slave dev promiscuity counter and sets
bond_info->primary_is_promisc = 1.

Because bond->curr_active_slave was prematurely cleared to NULL when
releasing the backup slave, the subsequent iteration releasing the active
slave evaluates oldcurrent as NULL, so bond_change_active_slave(bond, NULL)
is skipped. Consequently, bond_alb_handle_active_change() is never called
to decrement the promiscuity counter, permanently leaking promiscuous
mode on the physical device after bond teardown.

When oldcurrent == slave, bond_change_active_slave(bond, NULL) already sets
bond->curr_active_slave to NULL. We only need to avoid selecting a new
active slave when all == true. Replace the if (all) branch with
if (!all && oldcurrent == slave).

## Which versions are affected by CVE-2026-98074?


## How do I fix CVE-2026-98074?

Apply the vendor's patch.

## Is CVE-2026-98074 being exploited?

There is no known exploitation of CVE-2026-98074 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98074 and fix it if it is affected.

What it is: CVE-2026-98074 is a denial of service vulnerability in Linux, published on 25 Sep 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-2026-98074 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-2026-98074/ (Markdown: https://insights.sbomify.com/CVE-2026-98074/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98074
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98074
- OSV: https://osv.dev/vulnerability/CVE-2026-98074

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98074/
Summaries are generated and may contain mistakes; the official description above is the record.