# CVE-2017-7979: Denial of service in n/a

> Local users can cause a system hang or crash via uninitialized memory access in the Linux kernel packet action API.

- **Severity:** High 7.8 (`CVSS:3.0/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:** No
- **Published:** 19 Apr 2017
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-94wh-pgqj-7f7r

## What is CVE-2017-7979?

CVE-2017-7979 is a high-severity denial of service vulnerability in Linux kernel, published on 19 Apr 2017. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

The cookie feature in the packet action API implementation in net/sched/act_api.c in the Linux kernel 4.11.x through 4.11-rc7 mishandles the tb nlattr array, which allows local users to cause a denial of service (uninitialized memory access and refcount underflow, and system hang or crash) or possibly have unspecified other impact via "tc filter add" commands in certain contexts. NOTE: this does not affect stable kernels, such as 4.10.x, from kernel.org.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2017-7979?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2017-7979?

No fix has been published for CVE-2017-7979 yet. Limit exposure of the affected software until one is available.

## Is CVE-2017-7979 being exploited?

There is no known exploitation of CVE-2017-7979 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-7979 and fix it if it is affected.

What it is: CVE-2017-7979 is a high-severity denial of service vulnerability in Linux kernel, published on 19 Apr 2017. 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-2017-7979 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2017-7979/ (Markdown: https://insights.sbomify.com/CVE-2017-7979/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-7979
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-7979
- OSV: https://osv.dev/vulnerability/CVE-2017-7979

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-7979/
Summaries are generated and may contain mistakes; the official description above is the record.