Bug 2569618 (CVE-2026-124249)

Summary:	CVE-2026-124249 python: Python: Unauthorized cross-domain cookie deletion via expired Set-Cookie headers
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	bbrownin, cahl, dfreiber, dkeler, drow, gbenhaim, jburrell, jlanda, kshier, ljawale, msilmser, niyer, rbobbitt, rhel-process-autobot, simaishi, stcannon, suppawar, thason, twaugh, vkumar, watson-tool-maintainers, yguenane
Target Milestone:	---	Keywords:	Security
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Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in Python. A remote malicious server can cause unauthorized deletion of cookies belonging to unrelated domains from a shared cookie store. When processing an HTTP response that includes an already expired cookie header, Python's cookie handling mechanism removes stored cookies matching the header's domain and path without validating them against the cookie policy. This flaw allows an attacker to selectively evict legitimate cookies belonging to third-party domains, potentially disrupting active user sessions.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-11-10 13:15:07 UTC

http.cookiejar.CookieJar deleted a stored cookie when a response carried an
already expired Set-Cookie header for it, using the Domain and Path
attributes from the header without consulting the cookie policy. A server
could therefore delete cookies belonging to other domains from a shared
cookie jar, such as the one used by urllib's HTTPCookieProcessor. The fix
consults the cookie policy before an expired cookie may delete an existing
one, as required by RFC 6265 section 5.3.