The WEBrick gem 1.4.2 for Ruby allows directory traversal if the attacker once had local access to create a symlink to a location outside o…

published 2019-05-10 7y ago modified 2026-06-17 4mo ago also EUVD-2019-3538

cvss: 5.5; version 3.0, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 46%
public exploits: 0; none known

The WEBrick gem 1.4.2 for Ruby allows directory traversal if the attacker once had local access to create a symlink to a location outside of the web root directory. NOTE: The vendor states that this is analogous to Options FollowSymlinks in the Apache HTTP Server, and therefore it is "not a problem.

Is CVE-2019-11879 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Exploit prediction

0.55% chance of exploitation in the next 30 days, higher than 46% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
NVD	3.0	5.5	CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
NVD	2.0	2.1	AV:L/AC:L/Au:N/C:P/I:N/A:N

Classification

Weakness

CWE-22 Improper Limitation of a Pathname to a Restricted Directory
CWE-59 Improper Link Resolution Before File Access

References

bugs.ruby-lang.org /issues/15835
issue-tracking, vendor-advisory

Sources

CVE List CVE-2019-11879
NVD CVE-2019-11879

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.