Bug 2559220 (CVE-2026-114613)

Summary:	CVE-2026-114613 msgpack: msgpack: Denial of Service via memory leak during map deserialization
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	akhatavk, alinfoot, anthomas, aos-team-art-private, aprice, asdas, bbrownin, doconnor, dpaolell, dschmidt, dtrifiro, eglynn, ehelms, gbenhaim, ggainey, hoberger, ilpinto, jdelft, jdobes, jholecek, jjoyce, jlanda, jmitchel, jpasqual, jpretori, jsamir, jschluet, jupierce, juwatts, jwong, kaycoth, kgaikwad, kshier, lgarciaa, lhh, lpele, ltomasbo, mbiarnes, mburns, mdellweg, mgarciac, mhulan, mwoodson, niyer, nmoumoul, oezr, omaciel, orabin, osousa, pcreech, ppalepu, ppostler, prdhamdh, rbobbitt, rchan, rhel-process-autobot, sarad, sghai, sidsharm, simaishi, smallamp, sprizend, stcannon, suppawar, tmalecek, twaugh, vlaad, watson-tool-maintainers, weaton, yguenane, ykashtan, zzhou
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in msgpack. A remote attacker could trigger a memory leak by sending specially crafted MessagePack data containing rejected map keys during deserialization. Repeated transmission of such malformed inputs can lead to excessive process memory consumption, resulting in a Denial of Service (DoS) for the affected application.	Story Points:	---
Clone Of:		Environment:
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2560589, 2560590, 2560591, 2560598, 2560599, 2560603, 2560605, 2560593, 2560594, 2560595, 2560596, 2560600, 2560601, 2560602, 2560604, 2560606, 2560607
Bug Blocks:

Description OSIDB Bzimport 2026-10-22 18:42:22 UTC

MessagePack is the serializer implementation for Python msgpack.org. Prior to 1.2.3, the msgpack-python C extension (msgpack._cmsgpack) leaks a decoded map value when deserialization rejects a key with strict_map_key=True (the default). Repeated malformed inputs can cause unbounded process memory growth and denial of service in applications that deserialize attacker-controlled MessagePack data. Both unpackb() and the streaming Unpacker API are affected. The pure-Python fallback does not exhibit this leak in the reported tests. This issue is fixed in version 1.2.3.