Bug 2525639 (CVE-2026-56854)

Summary:	CVE-2026-56854 golang.org/x/crypto/ssh: golang.org/x/crypto/ssh: Authentication bypass due to unenforced source-address restrictions
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	urgent	Docs Contact:
Priority:	urgent
Version:	unspecified	CC:	aazores, akhatavk, akoudelk, amctagga, anjoseph, aoconnor, aos-team-art-private, aruklets, asdas, bniver, cmah, crizzo, dakwon, dhanak, dkeler, doconnor, dpaolell, drosa, dsimansk, dymurray, eaguilar, ebaron, eborisov, eglynn, flucifre, gbenhaim, gmeno, gparvin, groman, jburrell, jdelft, jeder, jjoyce, jmatsuok, jmatthew, jprabhak, jpretori, jschluet, jtolenti, jupierce, kingland, lball, lbragsta, lchilton, lgamliel, lgarciaa, lhh, mbenjamin, mbiarnes, mburns, mgarciac, mhackett, mnovotny, ngough, niyer, pjindal, ppalepu, ppostler, prdhamdh, rekumar, rhaigner, rhel-process-autobot, rjohnson, sausingh, sbratsla, sdawley, sfeifer, sghai, sidsharm, sostapov, suppawar, thason, twaugh, vereddy, veshanka, vkarehfa, vlaad, vvoronko, watson-tool-maintainers, wenshen, whayutin, wtam
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
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Doc Text:	A flaw was found in golang.org/x/crypto/ssh. The component failed to properly enforce source-address restrictions for several authentication methods, including password and keyboard-interactive callbacks. This oversight could allow a remote attacker to bypass intended network-based access controls, potentially leading to unauthorized access to services utilizing the affected component.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-08-28 15:33:57 UTC

The source-address critical option in the Permissions returned by an authentication callback was only enforced for the PublicKeyCallback and VerifiedPublicKeyCallback paths, extending the fix for CVE-2026-46595. Permissions returned by the PasswordCallback, KeyboardInteractiveCallback, NoClientAuthCallback, and GSSAPIWithMICConfig.AllowLogin callbacks were not validated against the client's remote address, so a source-address restriction set by those callbacks was silently ignored. The check is now applied to the Permissions returned by any authentication callback.