# CVE-2016-3947: Memory corruption in n/a

> Remote attackers can cause denial of service or leak sensitive data to logs via crafted ICMPv6 packets in the Squid pinger utility.

- **Severity:** High 8.2 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 7 Apr 2016
- **Updated:** 6 Aug 2024
- **Also known as:** DEBIAN-CVE-2016-3947, GHSA-59fp-mgp3-qph8, UBUNTU-CVE-2016-3947

## What is CVE-2016-3947?

CVE-2016-3947 is a high-severity memory corruption vulnerability in Canonical Ubuntu Linux, published on 7 Apr 2016. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Heap-based buffer overflow in the Icmp6::Recv function in icmp/Icmp6.cc in the pinger utility in Squid before 3.5.16 and 4.x before 4.0.8 allows remote servers to cause a denial of service (performance degradation or transition failures) or write sensitive information to log files via an ICMPv6 packet.

Weakness: CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2016-3947?

It affects 2 products.


Products: Canonical Ubuntu Linux, Squid-Cache Squid.

## How do I fix CVE-2016-3947?

Upgrade to a fixed version.

## Is CVE-2016-3947 being exploited?

There is no known exploitation of CVE-2016-3947 in the wild and no public exploit code.

## Other vulnerabilities in Canonical Ubuntu Linux

- [CVE-2020-11651](https://insights.sbomify.com/CVE-2020-11651/): SaltStack Salt Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2020-7247](https://insights.sbomify.com/CVE-2020-7247/): OpenSMTPD Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2019-16928](https://insights.sbomify.com/CVE-2019-16928/): Exim Out-of-bounds Write (critical 9.8, exploited in the wild)
- [CVE-2018-6789](https://insights.sbomify.com/CVE-2018-6789/): Exim Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2015-2590](https://insights.sbomify.com/CVE-2015-2590/): Oracle Java SE and Java SE Embedded Remote Code Execution (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-3947 and fix it if it is affected.

What it is: CVE-2016-3947 is a high-severity memory corruption vulnerability in Canonical Ubuntu Linux, published on 7 Apr 2016. 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-2016-3947 in the wild and no public exploit code.

Affected product: Canonical Ubuntu 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-2016-3947/ (Markdown: https://insights.sbomify.com/CVE-2016-3947/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-3947
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-3947
- OSV: https://osv.dev/vulnerability/CVE-2016-3947

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From sbomify Insights: https://insights.sbomify.com/CVE-2016-3947/
Summaries are generated and may contain mistakes; the official description above is the record.