# CVE-2026-74645: mm/damon/lru_sort: error out for >10000 active_mem_bp

> A local attacker with write access to module parameters can trigger a kernel divide-by-zero crash by setting an invalid active_mem_bp value.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 22 Aug 2026
- **Updated:** 22 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-74645, GHSA-pq4x-2prc-39cr, UBUNTU-CVE-2026-74645

## What is CVE-2026-74645?

CVE-2026-74645 is a denial of service vulnerability in Linux, published on 22 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:

mm/damon/lru_sort: error out for >10000 active_mem_bp

damos_quota_score() can trigger division by zero if the target value is
zero.  DAMON_LRU_SORT lets users set the target value for the hot memory
scheme via active_mem_bp parameter.  It avoids setting it as the target
value if the parameter value is zero.  However, it also sets the cold
memory scheme with a target value that is calculated as '10000 -
active_mem_bp + 2'.  Hence, if a user sets active_mem_bp 10002, the cold
memory scheme's quota goal target value can be zero.  As a result,
division by zero can be triggered.  Fix by returning an error when the
user tries to start DAMON with >10000 active_mem_bp parameter value.

It makes no sense to set active_mem_bp with 10002.  It also requires
module parameters write permission to reproduce the issue.  That said, the
consequence is quite bad.

One reliable way to reproduce the issue is like below:

    # cd /sys/module/damon_lru_sort/parameters
    # echo 1000 > wmarks_high
    # echo 995 > wmarks_mid
    # echo 0 > wmarks_low
    # echo 10002 > active_mem_bp
    # echo Y > enabled
    # dmesg -w
    [...]
    [  597.421247] Oops: divide error: 0000 [#1] SMP NOPTI
    [  597.428848] RIP: 0010:damos_quota_score+0x6f/0x480

This issue was discovered [1] by Sashiko.

## Which versions are affected by CVE-2026-74645?


## How do I fix CVE-2026-74645?

Apply the vendor's patch.

## Is CVE-2026-74645 being exploited?

There is no known exploitation of CVE-2026-74645 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74645 and fix it if it is affected.

What it is: CVE-2026-74645 is a denial of service vulnerability in Linux, published on 22 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-2026-74645 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-2026-74645/ (Markdown: https://insights.sbomify.com/CVE-2026-74645/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74645
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74645
- OSV: https://osv.dev/vulnerability/CVE-2026-74645

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-74645/
Summaries are generated and may contain mistakes; the official description above is the record.