# CVE-2026-98857: ipvs: bound LBLCR and LBLC cache growth

> An attacker can cause a denial of service in the Linux kernel IPVS module by exhausting memory through unbounded cache growth in LBLCR and LBLC schedulers.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 18 Oct 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-109176, BELL-CVE-2026-98857, DEBIAN-CVE-2026-98857, GHSA-3qgh-gjj6-qj8r, UBUNTU-CVE-2026-98857

## What is CVE-2026-98857?

CVE-2026-98857 is a denial of service vulnerability in Linux, published on 18 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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

ipvs: bound LBLCR and LBLC cache growth

ip_vs_lblcr_new() and ip_vs_lblc_new() create cache entries for
every previously unseen destination address. The table max_size only
tells the periodic collector to reclaim entries after the cache has
already exceeded the limit. It does not reclaim entries that the
attacker continues to use.

Reject new cache entries once either table reaches max_size * 3 / 2.
The extra headroom lets the periodic collector catch up while the
existing scheduler fallback continues to use the selected destination
when cache creation fails. New traffic therefore stays serviceable
without growing the tables further.

## Which versions are affected by CVE-2026-98857?


## How do I fix CVE-2026-98857?

Apply the vendor's patch.

## Is CVE-2026-98857 being exploited?

There is no known exploitation of CVE-2026-98857 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98857 and fix it if it is affected.

What it is: CVE-2026-98857 is a denial of service vulnerability in Linux, published on 18 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-98857 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-2026-98857/ (Markdown: https://insights.sbomify.com/CVE-2026-98857/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98857
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98857
- OSV: https://osv.dev/vulnerability/CVE-2026-98857

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98857/
Summaries are generated and may contain mistakes; the official description above is the record.