# CVE-2015-7977: Null dereference in n/a

> Remote attackers can cause a denial of service in the NTP daemon via a NULL pointer dereference triggered by a specific command.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/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:** 30 Jan 2017
- **Updated:** 6 Aug 2024
- **Also known as:** DEBIAN-CVE-2015-7977, GHSA-cvp4-369g-vpfx, UBUNTU-CVE-2015-7977

## What is CVE-2015-7977?

CVE-2015-7977 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 30 Jan 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

ntpd in NTP before 4.2.8p6 and 4.3.x before 4.3.90 allows remote attackers to cause a denial of service (NULL pointer dereference) via a ntpdc reslist command.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2015-7977?

It affects 10 products.


Products: Canonical Ubuntu Linux, Debian Debian Linux, Fedoraproject Fedora, Freebsd Freebsd, Netapp Clustered Data Ontap, Netapp Oncommand Balance, Ntp Ntp, Oracle Linux, Siemens Tim 4r-Ie Dnp3 Firmware, Siemens Tim 4r-Ie Firmware.

## How do I fix CVE-2015-7977?

Upgrade to a fixed version.

## Is CVE-2015-7977 being exploited?

There is no known exploitation of CVE-2015-7977 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-2015-7977 and fix it if it is affected.

What it is: CVE-2015-7977 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 30 Jan 2017. 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-2015-7977 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-2015-7977/ (Markdown: https://insights.sbomify.com/CVE-2015-7977/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2015-7977
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2015-7977
- OSV: https://osv.dev/vulnerability/CVE-2015-7977

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From sbomify Insights: https://insights.sbomify.com/CVE-2015-7977/
Summaries are generated and may contain mistakes; the official description above is the record.