Bug 2543860 (CVE-2026-77185)

Summary:	CVE-2026-77185 org.apache.sshd/sshd-core: Apache MINA SSHD: Asynchronous authentication can bypass signature verification
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	anujha, aschwart, asoldano, aszczucz, bbaranow, bmaxwell, boliveir, bstansbe, dlofthou, drichtar, fmariani, fmongiar, gmalinko, istudens, ivassile, iweiss, janstey, jnethert, jwon, mcarlett, mosmerov, mposolda, msvehla, nwallace, pberan, pdelbell, pesilva, pjindal, pmackay, rhel-process-autobot, rmartinc, rstancel, rstepani, ssilvert, sthorger, tcunning, thjenkin, vdosoudi, vmuzikar, watson-tool-maintainers, yfang
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 Apache MINA SSHD. When a Secure Shell (SSH) server implements the asynchronous authentication feature, a logic error in signature verification can result in public-key or host-based authentication checks being skipped. A remote, unauthenticated attacker can exploit this flaw to bypass authentication and gain unauthorized access to the server.	Story Points:	---
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Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-30 10:10:32 UTC

Authentication bypass in sshd-core in Apache MINA SSHD versions 2.0.0 to 2.19.0 and 3.0.0-M1 to 3.0.0-M5 for a certain (presumed rare) way to implement an SSH server.




Apache MINA SSHD is a Java library for client- and server-side SSH. In the server part of the library, a mechanism to perform "asynchronous authentication" exists. A server implemented with Apache MINA SSHD must contain explicit code to make use of this feature. The implementation of this feature was flawed and could potentially lead to skipping checking the signature in public-key or hostbased authentication, or returning a wrong result.




Users are recommended to upgrade to Apache MINA SSHD 2.20.0 or 3.0.0-M6, which fix the logic error and which additionally forbid the use of this "asynchronous authentication" mechanism with the public-key or hostbased authentication schemes: if used, the SSH session will be closed and the server will log an entry indicating that asynchronous authentication may be used only with password or keyboard-interactive authentication.