---
title: "CVE-2019-7303\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2019-7303?format=md
keywords: index, follow
---

# CVE-2019-7303

Publication date 21 March 2019

Last updated 25 August 2025

---

Ubuntu priority

**Medium**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

## Cvss 3 Severity Score

**7.5 · High**

[Score breakdown](https://ubuntu.com/security/CVE-2019-7303?format=md#impact-score)

Toggle side navigation

## Description

A vulnerability in the seccomp filters of Canonical snapd before version
2.37.4 allows a strict mode snap to insert characters into a terminal on a
64-bit host. The seccomp rules were generated to match 64-bit ioctl(2)
commands on a 64-bit platform; however, the Linux kernel only uses the
lower 32 bits to determine which ioctl(2) commands to run. This issue
affects: Canonical snapd versions prior to 2.37.4.

[Read the notes from the security team](https://ubuntu.com/security/CVE-2019-7303?format=md#notes)

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| snapd | 18.10 cosmic | Fixed 2.37.4+18.10 |
| 18.04 LTS bionic | Fixed 2.37.4+18.04.1 |
| 16.04 LTS xenial | Fixed 2.37.4ubuntu0.1 |
| 14.04 LTS trusty | Fixed 2.37.4~14.04.1 |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)
* [Patch details](https://ubuntu.com/security/CVE-2019-7303?format=md#patch-details)

## Notes

---

### [jdstrand](https://launchpad.net/~jdstrand)

this is a kernel limitation that is documented in the seccomp man
page, but arguably the kernel should perform the seccomp filter check on the
value that it is ultimately going to process (which likely means an
improvement to libseccomp to generate the appropriate BPF to do this)
this was further complicated by the fact that the kernel and glibc
disagree on the function prototype of ioctl, where the glibc man page
documents it as unsigned long and the kernel treats it as int (note, the
tty\_ioctl man page (which is the one that documents TIOCSTI) lists the ioctl
second argument as an int)
due to miscoordination, 2.37.4 is going to -updates first as part of
the regular SRU cycle. Once that passes, we'll rebuild and publish to the
security pocket and issue a USN.
once this issue is public, the global profile initialization code
that is used to address this issue will also be made public

### Patch details

For informational purposes only. We recommend not to cherry-pick updates. [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)

| Package | Patch details |
| --- | --- |
| snapd | * Upstream:   <https://github.com/snapcore/snapd/pull/6516> * Upstream:   <https://github.com/snapcore/snapd/pull/6533> |

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

7.5 · High

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Network |
  | Attack complexity | Low |
  | Privileges required | None |
  | User interaction | None |
  | Scope | Unchanged |
  | Confidentiality impact | None |
  | Integrity impact | High |
  | Availability impact | None |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 7.5 · High |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-7303)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2019-7303)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2019-7303)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2019-7303)

### Related Ubuntu Security Notices (USN)

+ [USN-3917-1](https://usn.ubuntu.com/USN-3917-1)
+ snapd vulnerability
+ 21 March 2019

### Other references

* <https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/SnapIoctlTIOCSTI>
* <https://www.cve.org/CVERecord?id=CVE-2019-7303>