CVE-2023-30571 — Libarchive through 3

Libarchive through 3.6.2 can cause directories to have world-writable permissions. The umask() call inside archive_write_disk_posix.c changes the umask of the whole process for a very short period of time; a race condition with another thread can lead to a permanent umask 0 setti

01What is this vulnerability?

Libarchive through 3.6.2 can cause directories to have world-writable permissions. The umask() call inside archive_write_disk_posix.c changes the umask of the whole process for a very short period of time; a race condition with another thread can lead to a permanent umask 0 setting. Such a race condition could lead to implicit directory creation with permissions 0777 (without the sticky bit)…

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: 2023-05-29T00:00:00.000Z
• Last modified: 2025-01-14T17:07:29.493Z

09References

• groups.google.com — https://groups.google.com/g/libarchive-announce
• github.com — https://github.com/libarchive/libarchive/issues/1876