# OSV-2020-2100: Bad-cast to pcpp::IDnsResource from invalid vptr

> A bad cast vulnerability in the PcapPlusPlus library allows attackers to cause memory corruption and potential code execution via crafted DNS packets.

- **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:** 28 Oct 2020

## What is OSV-2020-2100?

OSV-2020-2100 is a memory corruption vulnerability in pcapplusplus, published on 28 Oct 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=26669

```
Crash type: Bad-cast
Crash state:
Bad-cast to pcpp::IDnsResource from invalid vptr
pcpp::DnsLayer::parseResources
pcpp::DnsLayer::DnsLayer
```

## Which versions are affected by OSV-2020-2100?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `pcapplusplus` | OSS-Fuzz | All versions | None |

## How do I fix OSV-2020-2100?

No fix has been published for OSV-2020-2100 yet. Limit exposure of the affected software until one is available.

## Is OSV-2020-2100 being exploited?

There is no known exploitation of OSV-2020-2100 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for OSV-2020-2100 and fix it if it is affected.

What it is: OSV-2020-2100 is a memory corruption vulnerability in pcapplusplus, published on 28 Oct 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of OSV-2020-2100 in the wild and no public exploit code.

Affected packages and fixed versions:
- pcapplusplus (OSS-Fuzz): 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/OSV-2020-2100/ (Markdown: https://insights.sbomify.com/OSV-2020-2100/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/OSV-2020-2100

---
From sbomify Insights: https://insights.sbomify.com/OSV-2020-2100/
Summaries are generated and may contain mistakes; the official description above is the record.