# CVE-2019-16056: Other in n/a > The Python email module incorrectly parses addresses with multiple @ symbols, allowing attackers to bypass header validation checks in applications using this library. - **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 6 Sep 2019 - **Updated:** 14 Oct 2026 - **Also known as:** ALPINE-CVE-2019-16056, AZL-109629, CLEANSTART-2026-VJ78698, DEBIAN-CVE-2019-16056, DLA-1924-1, DLA-1925-1, GHSA-8mcc-mjj5-h77m, PSF-2019-5, RHSA-2020:2520, SUSE-RU-2020:1342-1, SUSE-SU-2021:14198-1, UBUNTU-CVE-2019-16056 ## What is CVE-2019-16056? CVE-2019-16056 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 6 Sep 2019. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description An issue was discovered in Python through 2.7.16, 3.x through 3.5.7, 3.6.x through 3.6.9, and 3.7.x through 3.7.4. The email module wrongly parses email addresses that contain multiple @ characters. An application that uses the email module and implements some kind of checks on the From/To headers of a message could be tricked into accepting an email address that should be denied. An attack may be the same as in CVE-2019-11340; however, this CVE applies to Python more generally. Weakness: CWE-20 (Improper Input Validation) ## Which versions are affected by CVE-2019-16056? It affects 10 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `python` | Red Hat:rhel_eus:7.7::computenode | All versions | 0:2.7.5-87.el7_7 | | `python-debug` | Red Hat:rhel_eus:7.7::computenode | All versions | 0:2.7.5-87.el7_7 | | `python-debuginfo` | Red Hat:rhel_eus:7.7::computenode | All versions | 0:2.7.5-87.el7_7 | | `python-devel` | Red Hat:rhel_eus:7.7::computenode | All versions | 0:2.7.5-87.el7_7 | | `python-libs` | Red Hat:rhel_eus:7.7::computenode | All versions | 0:2.7.5-87.el7_7 | | `python-test` | Red Hat:rhel_eus:7.7::computenode | All versions | 0:2.7.5-87.el7_7 | | `python-tools` | Red Hat:rhel_eus:7.7::computenode | All versions | 0:2.7.5-87.el7_7 | | `tkinter` | Red Hat:rhel_eus:7.7::computenode | All versions | 0:2.7.5-87.el7_7 | | `python` | Red Hat:rhel_eus:7.7::server | All versions | 0:2.7.5-87.el7_7 | | `python-debug` | Red Hat:rhel_eus:7.7::server | All versions | 0:2.7.5-87.el7_7 | | `python-debuginfo` | Red Hat:rhel_eus:7.7::server | All versions | 0:2.7.5-87.el7_7 | | `python-devel` | Red Hat:rhel_eus:7.7::server | All versions | 0:2.7.5-87.el7_7 | | `python-libs` | Red Hat:rhel_eus:7.7::server | All versions | 0:2.7.5-87.el7_7 | | `python-test` | Red Hat:rhel_eus:7.7::server | All versions | 0:2.7.5-87.el7_7 | | `python-tools` | Red Hat:rhel_eus:7.7::server | All versions | 0:2.7.5-87.el7_7 | | `tkinter` | Red Hat:rhel_eus:7.7::server | All versions | 0:2.7.5-87.el7_7 | | `python3` | SUSE:Linux Enterprise Module for Basesystem 15 SP1 | All versions | 3.6.10-3.53.1 | | `python3-base` | SUSE:Linux Enterprise Module for Basesystem 15 SP1 | All versions | 3.6.10-3.53.1 | | `python3-base` | SUSE:Linux Enterprise Module for Development Tools 15 SP1 | All versions | 3.6.10-3.53.1 | | `python` | SUSE:Linux Enterprise Point of Sale 11 SP3 | All versions | 2.6.9-40.32.2 | | `python-base` | SUSE:Linux Enterprise Point of Sale 11 SP3 | All versions | 2.6.9-40.32.1 | | `python-doc` | SUSE:Linux Enterprise Point of Sale 11 SP3 | All versions | 2.6-8.40.32.1 | | `python` | SUSE:Linux Enterprise Server 11 SP4-LTSS | All versions | 2.6.9-40.32.2 | | `python-base` | SUSE:Linux Enterprise Server 11 SP4-LTSS | All versions | 2.6.9-40.32.1 | | `python-doc` | SUSE:Linux Enterprise Server 11 SP4-LTSS | All versions | 2.6-8.40.32.1 | Products: Canonical Ubuntu Linux, Debian Debian Linux, Fedoraproject Fedora, Opensuse Leap, Oracle Communications Operations Monitor, Oracle Peoplesoft Enterprise Peopletools, Oracle Solaris, Oracle Zfs Storage Appliance Kit, Python Python, Redhat Software Collections. ## How do I fix CVE-2019-16056? Upgrade to a fixed version. ## Is CVE-2019-16056 being exploited? There is no known exploitation of CVE-2019-16056 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-2019-16056 and fix it if it is affected. What it is: CVE-2019-16056 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 6 Sep 2019. 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-2019-16056 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-2019-16056/ (Markdown: https://insights.sbomify.com/CVE-2019-16056/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2019-16056 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-16056 - OSV: https://osv.dev/vulnerability/CVE-2019-16056 --- From sbomify Insights: https://insights.sbomify.com/CVE-2019-16056/ Summaries are generated and may contain mistakes; the official description above is the record.