CVE-2026-11940

CVE-2026-11940 is a high-severity vulnerability with a CVSS 4.0 base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-22.

Key facts

Description

tarfile.extractall() with the 'data' or 'tar' filter could be bypassed by a crafted archive where a hardlink references a symlink stored at a deeper name than the hardlink itself.  The extraction fallback validated the symlink at it's archived location but recreated it at the hardlink's shallower path, letting a relative target the filter judged contained escape the destination directory.  This allowed a malicious tar archive to create a symlink pointing outside the destination, enabling out-of-destination file reads or writes. This was an incomplete fix of CVE-2025-4330.

Frequently asked questions

What is CVE-2026-11940?
tarfile.extractall() with the 'data' or 'tar' filter could be bypassed by a crafted archive where a hardlink references a symlink stored at a deeper name than the hardlink itself.  The extraction fallback validated the symlink at it's archived location but recreated it at the hardlink's shallower path, letting a relative target the filter judged contained escape the destination directory.  This allowed a malicious tar archive to create a symlink pointing outside the destination, enabling out-of-destination file reads or writes. This was an incomplete fix of CVE-2025-4330.
How severe is CVE-2026-11940?
CVE-2026-11940 has a CVSS 4.0 base score of 7.8, rated high severity.
Is CVE-2026-11940 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-11940?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-11940 have an EU (EUVD) identifier?
Yes. CVE-2026-11940 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38490.
When was CVE-2026-11940 published?
CVE-2026-11940 was published on 2026-06-23 and last updated on 2026-06-30.

References

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