CVE-2026-66484: GNU cpio · Path Traversal
Affects GNU cpioSource CVE Database V5
Not known to be exploited · CVSS 4.6 Medium.
Data as of 7 Nov 2026, 23:24 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:L/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 10 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 8 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| GNUcpio | Affected
| Fixed in– |
AI-suggested
A fix for this vulnerability has been implemented in the referenced commit (e2b9cbdd3354d2b1569b7390d1bc15c1930559ad). Users should update GNU cpio to a version that includes this fix. Patch status is not explicitly confirmed in the advisory, so users should verify the presence of this commit or an official vendor update. Until patched, avoid extracting untrusted tar archives with the --no-absolute-filenames option or apply manual sanitization of hard-link targets.
Description
GNU cpio contains a Path Traversal vulnerability in its tar archive extraction functionality. When extracting a tar archive in copy-in mode with the --no-absolute-filenames option, the extracted file name is normalized but the tar hard-link target is passed to the link_to_name function without equivalent sanitization before calling link function. A tar archive provided by an attacker, containing a hard-link entry whose linkname is set to an absolute path outside the extraction directory, can cause cpio to create a hard link to an existing file outside the intended extraction directory, breaking the expected guarantee of --no-absolute-filenames and allowing archive-controlled linkage to external files. This issue has been fixed in commit e2b9cbdd3354d2b1569b7390d1bc15c1930559ad