Bug 2509762 (CVE-2026-68742)

Summary: CVE-2026-68742 sssd: sssd: NSS responder out-of-bounds read via unchecked addrlen in GETHOSTBYADDR
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, security-response-team, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in SSSD. The sss_nss_protocol_parse_addr() function in the NSS responder does not validate the addrlen field against the remaining packet body size. A local attacker can exploit this via a crafted GETHOSTBYADDR request to the NSS responder socket, causing an out-of-bounds read and process crash, resulting in a denial of service.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2510306    
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Description OSIDB Bzimport 2026-07-31 12:31:39 UTC 
A flaw was found in SSSD. The sss_nss_protocol_parse_addr() function in the NSS responder (src/responder/nss/nss_protocol.c) extracts a 32-bit addrlen value from the client request but only validates that the body is at least 8 bytes, without checking that addrlen fits within the remaining packet body. This unvalidated length is passed through to talloc_memdup() in cache_req_data_create(), which copies addrlen bytes from the small request buffer, causing a heap-buffer-overflow read. A local attacker can trigger this by connecting to the world-writable NSS responder socket (/var/lib/sss/pipes/nss) and sending a SSS_NSS_GETHOSTBYADDR (0x0053) request with a large addrlen value and a valid address family payload so that inet_ntop() succeeds. Successful exploitation crashes the sssd_nss responder, causing a denial of service for NSS name resolution. Reported via PSIRTSUPT-20553 by BreachX Zero Day Labs.