Bug 2480688 (CVE-2026-42508)

Summary: CVE-2026-42508 golang.org/x/crypto/ssh/knownhosts: golang: golang.org/x/crypto/ssh/knownhosts: Revocation bypass via unchecked SignatureKey
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: alcohan, amctagga, anjoseph, aoconnor, bbrownin, bdettelb, bniver, dhanak, doconnor, drosa, dsimansk, dymurray, eborisov, eglynn, fdeutsch, flucifre, gmeno, gparvin, groman, jbalunas, jjoyce, jkoehler, jmatthew, jprabhak, jpretori, jschluet, kingland, kverlaen, lball, lgamliel, lhh, lphiri, manissin, mbenjamin, mburns, mgarciac, mhackett, mnovotny, ngough, oramraz, pahickey, rfreiman, rhaigner, rhel-process-autobot, rjohnson, sausingh, sdawley, smullick, sostapov, stirabos, thason, vereddy, veshanka, watson-tool-maintainers, whayutin, wtam
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in golang.org/x/crypto/ssh/knownhosts. This vulnerability occurs because the system did not correctly check for the revocation status of a SignatureKey belonging to a Certificate Authority (CA). A remote attacker could potentially exploit this by presenting a revoked key, leading to the system accepting it as valid. This could allow an attacker to bypass security checks and potentially gain unauthorized access or spoof legitimate entities.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 2489773    
Bug Blocks:    

Description OSIDB Bzimport 2026-05-22 04:02:12 UTC 
Previously, a revoked 'SignatureKey' belonging to a CA was not correctly checked for revocation. Now, both the 'key' and 'key.SignatureKey' are checked for @revoked.