Bug 2556210 (CVE-2026-112912)

Summary:	CVE-2026-112912 filelock: filelock: Information disclosure via symbolic link following in SoftFileLock
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	akhatavk, alinfoot, anpicker, anthomas, aos-team-art-private, aprice, asdas, bbrownin, blitton, cahl, cmyers, dfreiber, dnakabaa, dpaolell, drow, dschmidt, dtrifiro, ebourniv, ehelms, gbenhaim, ggainey, hasun, hoberger, ilpinto, jburrell, jdelft, jdobes, jfula, jholecek, jlanda, jmitchel, jowilson, jpasqual, jsamir, jupierce, juwatts, jwong, kaycoth, kgaikwad, kshier, lcouzens, lgarciaa, ljawale, lpele, ltomasbo, mbarnett, mbiarnes, mdellweg, mhayden, mhulan, msilmser, mwoodson, niyer, nmoumoul, nyancey, oezr, omaciel, ometelka, orabin, osousa, pcreech, ppalepu, ppostler, prdhamdh, prwatson, ptisnovs, rbobbitt, rchan, sarad, sbunciak, sdawley, sdoran, sghai, sidsharm, simaishi, smallamp, sprizend, stcannon, suppawar, syedriko, tmalecek, twaugh, vkumar, vlaad, weaton, xdharmai, yguenane, ykashtan, zzhou
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
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Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in filelock. When SoftFileLock verifies file permissions during lock acquisition, it may follow an untrusted symbolic link. A local attacker could exploit this behavior in shared directories to infer whether a target file path exists and is writable, resulting in unauthorized information disclosure.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-10-20 14:43:51 UTC

filelock is a platform-independent file lock for Python. From 3.32.6 until 4.2.1, SoftFileLock can follow a swapped symbolic link during the conditional os.access writability check for a node without its owner-write bit, allowing another local user on a platform and directory configuration that follows the link to infer whether a chosen path exists and is writable from the observable acquisition result. This issue is fixed in version 4.2.1.