CVE-2018-20835 — A vulnerability was found in tar-fs before 1

A vulnerability was found in tar-fs before 1.16.2. An Arbitrary File Overwrite issue exists when extracting a tarball containing a hardlink to a file that already exists on the system, in conjunction with a later plain file with the same name as the hardlink. This plain file cont

01What is this vulnerability?

A vulnerability was found in tar-fs before 1.16.2. An Arbitrary File Overwrite issue exists when extracting a tarball containing a hardlink to a file that already exists on the system, in conjunction with a later plain file with the same name as the hardlink. This plain file content replaces the existing file content.

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2019-04-30T18:02:13.000Z
• Last modified: 2024-08-05T12:12:26.890Z

09References

• hackerone.com — https://hackerone.com/reports/344595
• github.com — https://github.com/mafintosh/tar-fs/commit/06672828e6fa29ac8551b1b6f36c852a9a3c5…
• github.com — https://github.com/mafintosh/tar-fs/compare/d590fc7...a35ce2f