{"id":"AZL-103413","summary":"CVE-2026-86805 affecting package glibc 2.38-21","details":"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.","modified":"2026-09-24T05:33:01Z","published":"2026-09-22T16:18:06Z","upstream":["CVE-2026-86805"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-86805"}],"affected":[{"package":{"name":"glibc","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/glibc"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"2.38-21"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-103413.json"}}],"schema_version":"1.9.0"}