Bug 2565690

Summary:	CVE-2026-120217 python-loguru: loguru: Denial of Service via inefficient regular expression complexity [fedora-43]
Product:	[Fedora] Fedora	Reporter:	Ganesh <gnaik>
Component:	python-loguru	Assignee:	Ben Beasley <code>
Status:	ON_QA ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	43	CC:	code, neuro-sig
Target Milestone:	---	Keywords:	Security, SecurityTracking
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["d8de1a50-9f36-4cda-92c0-63173ce59d6b"]}
Fixed In Version:		Doc Type:	---
Doc Text:		Story Points:	---
Clone Of:		Environment:
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Regression:	---	Mount Type:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	2564513

Description Ganesh 2026-11-03 11:03:04 UTC

Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

A vulnerability was detected in Delgan loguru 0.7.3. The affected element is the function AnsiParser.feed of the file loguru/_colorizer.py of the component ANSI Color-Markup Parser. Performing a manipulation results in inefficient regular expression complexity. The attack is possible to be carried out remotely. The exploit is now public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

Comment 1 Ben Beasley 2026-11-03 13:57:57 UTC

I reported this upstream. It has been a while since the last release, but the upstream developer has been active lately, so it’s reasonable to hope that they may come up with a patch in the near future. If that happens, I’ll apply it here. Meanwhile, anyone who is using the loguru Python package to log untrusted input should not configure their logger with color=True.

Comment 2 Fedora Update System 2026-11-04 08:02:40 UTC

FEDORA-2026-ea090e0910 (python-loguru-0.7.3-23.fc43) has been submitted as an update to Fedora 43.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-ea090e0910

Comment 3 Fedora Update System 2026-11-05 16:08:15 UTC

FEDORA-2026-ea090e0910 has been pushed to the Fedora 43 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-ea090e0910`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-ea090e0910

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.