# GSD-2021-1000747: ipv6: Fix KASAN: slab-out-of-bounds Read in fib6_nh_flush_exceptions

> A slab-out-of-bounds read in the Linux kernel IPv6 subsystem can cause a denial of service, requiring a kernel patch.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 25 Jun 2021

## What is GSD-2021-1000747?

GSD-2021-1000747 is a memory corruption vulnerability in Kernel, published on 25 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

ipv6: Fix KASAN: slab-out-of-bounds Read in fib6_nh_flush_exceptions

This is an automated ID intended to aid in discovery of potential security vulnerabilities. The actual impact and attack plausibility have not yet been proven.
This ID is fixed in Linux Kernel version v5.4.125 by commit 7ba7fa78a92dc410b6f93ed73075ab669c3a0b59, it was introduced in version v5.3 by commit f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74. For more details please see the references link.

## Which versions are affected by GSD-2021-1000747?

1 open source package ship an affected version, including Kernel.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `Kernel` | Linux | All versions | None |

## How do I fix GSD-2021-1000747?

No fix has been published for GSD-2021-1000747 yet. Limit exposure of the affected software until one is available.

## Is GSD-2021-1000747 being exploited?

There is no known exploitation of GSD-2021-1000747 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GSD-2021-1000747 and fix it if it is affected.

What it is: GSD-2021-1000747 is a memory corruption vulnerability in Kernel, published on 25 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of GSD-2021-1000747 in the wild and no public exploit code.

Affected packages and fixed versions:
- Kernel (Linux): affected all versions; no fix listed

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/GSD-2021-1000747/ (Markdown: https://insights.sbomify.com/GSD-2021-1000747/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GSD-2021-1000747

---
From sbomify Insights: https://insights.sbomify.com/GSD-2021-1000747/
Summaries are generated and may contain mistakes; the official description above is the record.