{"id":"CVE-2026-86805","state":"PUBLISHED","title":"AT_SECURE programs may load attacker-controlled code via $ORIGIN","description":"A time-of-check to time-of-use (TOCTOU) race condition in the dynamic loader (ld.so) of the GNU C Library (glibc) versions 2.14 through 2.44 allows a local attacker to escalate privileges. When expanding $ORIGIN in DT_RPATH for setuid/setgid (AT_SECURE) programs, glibc validates the lexically normalized search path against the trusted directories but then opens the raw, un-normalized path. On systems where the Linux fs.protected_hardlinks sysctl is disabled, a local attacker who hard-links such a program into an attacker-controlled directory and wins a race to replace an intermediate path component with a symbolic link can direct the loader outside the trusted directory, causing it to load an attacker-controlled shared object and execute arbitrary code with the elevated privileges of the program.\n\nExploitation requires an installed setuid or setgid binary whose DT_RPATH uses $ORIGIN followed by \"..\" traversal that normalizes into a trusted directory, and the ability to hard-link that binary and win the race by swapping a path component for a symbolic link. Major Linux-based OS distributions ship with fs.protected_hardlinks enabled by default and mitigate the vulnerability.","publishedAt":"2026-09-22T15:55:17.117Z","updatedAt":"2026-09-23T03:55:58.505Z","severity":{"score":6.3,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:L","source":"glibc"},"assigner":"glibc","products":["The GNU C Library glibc"],"affected":[{"vendor":"The GNU C Library","product":"glibc","defaultStatus":"unaffected","versions":[{"version":"2.14","status":"affected","lessThan":"2.45","versionType":"custom"}]}],"references":["https://sourceware.org/bugzilla/show_bug.cgi?id=34360","https://sourceware.org/git/?p=glibc.git;a=blob_plain;f=advisories/GLIBC-SA-2026-0022"],"weaknesses":["CWE-367"],"ingestedAt":"2026-10-29T20:13:26.108Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/86xxx/CVE-2026-86805.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-86805","state":"PUBLISHED","datePublished":"2026-09-22T15:55:17.117Z","dateUpdated":"2026-09-23T03:55:58.505Z","assignerShortName":"glibc","assignerOrgId":"3ff69d7a-14f2-4f67-a097-88dee7810d18","dateReserved":"2026-09-08T12:56:00.982Z"},"containers":{"cna":{"title":"AT_SECURE programs may load attacker-controlled code via $ORIGIN","descriptions":[{"lang":"en","value":"A time-of-check to time-of-use (TOCTOU) race condition in the dynamic loader (ld.so) of the GNU C Library (glibc) versions 2.14 through 2.44 allows a local attacker to escalate privileges. When expanding $ORIGIN in DT_RPATH for setuid/setgid (AT_SECURE) programs, glibc validates the lexically normalized search path against the trusted directories but then opens the raw, un-normalized path. On systems where the Linux fs.protected_hardlinks sysctl is disabled, a local attacker who hard-links such a program into an attacker-controlled directory and wins a race to replace an intermediate path component with a symbolic link can direct the loader outside the trusted directory, causing it to load an attacker-controlled shared object and execute arbitrary code with the elevated privileges of the program.\n\nExploitation requires an installed setuid or setgid binary whose DT_RPATH uses $ORIGIN followed by \"..\" traversal that normalizes into a trusted directory, and the ability to hard-link that binary and win the race by swapping a path component for a symbolic link. Major Linux-based OS distributions ship with fs.protected_hardlinks enabled by default and mitigate the vulnerability."}],"affected":[{"vendor":"The GNU C Library","product":"glibc","defaultStatus":"unaffected","versions":[{"version":"2.14","status":"affected","lessThan":"2.45","versionType":"custom"}]}],"references":[{"url":"https://sourceware.org/bugzilla/show_bug.cgi?id=34360","tags":["issue-tracking"]},{"url":"https://sourceware.org/git/?p=glibc.git;a=blob_plain;f=advisories/GLIBC-SA-2026-0022","tags":["vendor-advisory"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"version":"3.1","attackVector":"LOCAL","attackComplexity":"HIGH","privilegesRequired":"LOW","userInteraction":"REQUIRED","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"LOW","baseSeverity":"MEDIUM","baseScore":6.3,"vectorString":"CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:L"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-367","lang":"en","description":"CWE-367 Time-of-check time-of-use (TOCTOU) race condition","type":"CWE"}]}],"providerMetadata":{"shortName":"glibc","orgId":"3ff69d7a-14f2-4f67-a097-88dee7810d18","dateUpdated":"2026-09-22T16:42:16.362Z"},"impacts":[{"capecId":"CAPEC-233","descriptions":[{"lang":"en","value":"CAPEC-233 Privilege Escalation"}]}],"credits":[{"lang":"en","value":"Jann Horn","type":"finder"}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"Vulnogram 1.0.5"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-22T00:00:00+00:00","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3","id":"CVE-2026-86805"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-23T03:55:58.505Z"}}]}}}