CVE-2026-39822: high-severity vulnerability in Go standard library os
Root escape via symlink plus trailing slash in os
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.8epss 0.2%
On Unix systems, opening a file in an os.Root improperly follows symlinks to locations outside of the Root when the final path component of the a path is a symbolic link and the path ends in /. For example, 'root.Open("symlink/")' will open "symlink" even when "symlink" is a symbolic link pointing outside of the root.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Affected products
Go standard library · osRelated CVEs — Go standard library os
In the same product, most dangerous first.
CVE-2022-41720HIGHRestricted file access on Windows in os and net/httpEPSS 1.3%CVE-2026-56857CRITICALRoot.Mkdir(All) can follow junctions out of the root on Windows in osEPSS 0.6%CVE-2025-0913MEDIUMInconsistent handling of O_CREATE|O_EXCL on Unix and Windows in os in syscallEPSS 0.3%CVE-2025-22873LOWImproper access to parent directory of root in osEPSS 0.2%CVE-2026-27139LOWFileInfo can escape from a Root in osEPSS 0.2%