{"id":"CVE-2026-89092","state":"PUBLISHED","title":"Stack overflow in nscd due to unbounded alloca use","description":"The nscd service in the GNU C Library 2.3.4 onwards may crash due to a \nstack overflow when a malicious DNS server returns too large a response \nfor a DNS query, resulting in degraded DNS resolution for the system.\n\n\n\nExploitation of this bug needs a system that has nscd enabled and using \nan untrusted DNS server for name resolution, with the compromised DNS \nserver being capable of processing records large enough to result in a \nstack overflow in an nscd thread stack.  During experimentation, bind 9 \nwas unable to handle large records, but that could change in future or \nwith a different name server.  In typical installations, nscd is \nexecuted in an isolated context as its own user without a shell, due to \nwhich any compromise of that service is isolated.\n\n\n\nThere is a remote possibility of nscd cache corruption if an attacker \nmanages to get the stack pointer into a desired point in the heap, \npotentially resulting in other caches in nscd being overwritten with \ncorrupt data through the stack overflow, until the buggy code path \neventually results in a crash.\n\n\n\nFinally, a crash in nscd may result in performance degradation when \nresolving names, but it does not result in a denial of service.","publishedAt":"2026-09-11T01:23:01.162Z","updatedAt":"2026-09-11T17:02:18.288Z","severity":{"score":4.2,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L","source":"glibc"},"assigner":"glibc","products":["The GNU C Library glibc"],"affected":[{"vendor":"The GNU C Library","product":"glibc","defaultStatus":"unaffected","versions":[{"version":"2.3.4","status":"affected","lessThan":"2.45","versionType":"custom"}]}],"references":["https://sourceware.org/bugzilla/show_bug.cgi?id=34624","https://sourceware.org/git/?p=glibc.git;a=blob_plain;f=advisories/GLIBC-SA-2026-0016","http://www.openwall.com/lists/oss-security/2026/09/11/2"],"weaknesses":["CWE-789"],"ingestedAt":"2026-10-29T20:13:26.108Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/89xxx/CVE-2026-89092.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-89092","state":"PUBLISHED","datePublished":"2026-09-11T01:23:01.162Z","dateUpdated":"2026-09-11T17:02:18.288Z","assignerShortName":"glibc","assignerOrgId":"3ff69d7a-14f2-4f67-a097-88dee7810d18","dateReserved":"2026-09-10T20:18:09.584Z"},"containers":{"cna":{"title":"Stack overflow in nscd due to unbounded alloca use","descriptions":[{"lang":"en","value":"The nscd service in the GNU C Library 2.3.4 onwards may crash due to a \nstack overflow when a malicious DNS server returns too large a response \nfor a DNS query, resulting in degraded DNS resolution for the system.\n\n\n\nExploitation of this bug needs a system that has nscd enabled and using \nan untrusted DNS server for name resolution, with the compromised DNS \nserver being capable of processing records large enough to result in a \nstack overflow in an nscd thread stack.  During experimentation, bind 9 \nwas unable to handle large records, but that could change in future or \nwith a different name server.  In typical installations, nscd is \nexecuted in an isolated context as its own user without a shell, due to \nwhich any compromise of that service is isolated.\n\n\n\nThere is a remote possibility of nscd cache corruption if an attacker \nmanages to get the stack pointer into a desired point in the heap, \npotentially resulting in other caches in nscd being overwritten with \ncorrupt data through the stack overflow, until the buggy code path \neventually results in a crash.\n\n\n\nFinally, a crash in nscd may result in performance degradation when \nresolving names, but it does not result in a denial of service."}],"affected":[{"vendor":"The GNU C Library","product":"glibc","defaultStatus":"unaffected","versions":[{"version":"2.3.4","status":"affected","lessThan":"2.45","versionType":"custom"}]}],"references":[{"url":"https://sourceware.org/bugzilla/show_bug.cgi?id=34624","tags":["issue-tracking"]},{"url":"https://sourceware.org/git/?p=glibc.git;a=blob_plain;f=advisories/GLIBC-SA-2026-0016","tags":["vendor-advisory"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"version":"3.1","attackVector":"ADJACENT_NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"LOW","availabilityImpact":"LOW","baseSeverity":"MEDIUM","baseScore":4.2,"vectorString":"CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-789","lang":"en","description":"CWE-789 Memory allocation with excessive size value","type":"CWE"}]}],"providerMetadata":{"shortName":"glibc","orgId":"3ff69d7a-14f2-4f67-a097-88dee7810d18","dateUpdated":"2026-09-11T01:23:01.162Z"},"impacts":[{"capecId":"CAPEC-142","descriptions":[{"lang":"en","value":"CAPEC-142 DNS Cache Poisoning"}]}],"credits":[{"lang":"en","value":"Anmol Singh Rajput","type":"finder"}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"Vulnogram 1.0.5"}},"adp":[{"title":"CVE Program Container","references":[{"url":"http://www.openwall.com/lists/oss-security/2026/09/11/2"}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2026-09-11T03:09:09.108Z"}},{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-11T16:57:22.665457Z","id":"CVE-2026-89092","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA 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