Directory traversal on Windows

• https://github.com/mojolicious/mojo/issues/738
• https://github.com/mojolicious/mojo/commit/9ffa38fca73a9ddee91cbc70e0696268d500edde

Context sensitivity of method param could lead to parameter injection attacks.

• https://github.com/mojolicious/mojo/commit/a815d4797145f872ef6e9f1270841eda1d410afb

Mojolicious is vulnerable to cross-site scripting, caused by improper validation of user-supplied input by link_to helper. A remote attacker could exploit this vulnerability using a specially-crafted URL to execute script in a victim's Web browser within the security context of the hosting Web site, once the URL is clicked. An attacker could use this vulnerability to steal the victim's cookie-based authentication credentials.

• https://exchange.xforce.ibmcloud.com/vulnerabilities/67257
• https://www.debian.org/security/2011/dsa-2239
• https://github.com/mojolicious/mojo/commit/f6801ef7be8c78092e38f870b19fae3da0899d60

Directory traversal vulnerability in Path.pm in Mojolicious before 1.16 allows remote attackers to read arbitrary files via a %2f..%2f (encoded slash dot dot slash) in a URI.

• https://github.com/mojolicious/mojo/commit/b09854988c5b5b6a2ba53cc8661c4b2677da3818
• https://www.cvedetails.com/cve/CVE-2011-1589/

Cross-site scripting (XSS) vulnerability in the link_to helper in Mojolicious before 1.12 allows remote attackers to inject arbitrary web script or HTML via unspecified vectors.

• http://cpansearch.perl.org/src/KRAIH/Mojolicious-1.20/Changes
• http://lists.fedoraproject.org/pipermail/package-announce/2011-May/060122.html
• http://www.debian.org/security/2011/dsa-2239
• http://www.securityfocus.com/bid/47713
• https://exchange.xforce.ibmcloud.com/vulnerabilities/67257

Mojo::DOM did not correctly parse <script> tags.

• https://github.com/mojolicious/mojo/commit/6f195d85db6756022d3599f7d2634975688c9550
• https://github.com/mojolicious/mojo/issues/2014
• https://github.com/mojolicious/mojo/issues/2015

Small sessions could be used as part of a brute-force attack to decode the session secret.

• https://github.com/mojolicious/mojo/pull/1791

A bug in format detection can potentially be exploited for a DoS attack.

• https://github.com/mojolicious/mojo/issues/1736
• https://github.com/mojolicious/mojo/commit/a0c4576ffb11c235088550de9ba7ac4196e1953c

Mojo::UserAgent was not checking peer SSL certificates by default.

• https://github.com/mojolicious/mojo/pull/1226
• https://github.com/mojolicious/mojo/commit/d3cbbad890673612fdbdea63fdd522b516f6104c

GET requests with embedded backslashes can be used to access local files on Windows hosts

• https://github.com/mojolicious/mojo/pull/1217
• https://github.com/mojolicious/mojo/commit/23ebe051d9378f0f122e3c908845fc0c2cae0106

Mojo::UserAgent::CookieJar leaks old cookies because of the missing host_only flag on empty domain.

• https://github.com/mojolicious/mojo/pull/1192
• https://github.com/mojolicious/mojo/issues/1185
• https://github.com/mojolicious/mojo/commit/c16a56a9d6575ddc53d15e76d58f0ebcb0eeb149

Mojolicious versions from 0.999922 for Perl uses a hard coded string, or the application's class name, as an HMAC session cookie secret by default. These predictable default secrets can be exploited by an attacker to forge session cookies.  An attacker who knows or guesses the secret could compute valid HMAC signatures for the session cookie, allowing them to tamper with or hijack another user’s session.

• https://github.com/mojolicious/mojo/pull/1791
• https://github.com/mojolicious/mojo/pull/2200
• https://www.synacktiv.com/publications/baking-mojolicious-cookies
• https://medium.com/securing/baking-mojolicious-cookies-revisited-a-case-study-of-solving-security-problems-through-security-by-13da7c225802
• https://metacpan.org/release/SRI/Mojolicious-9.39/source/lib/Mojolicious.pm#L51
• https://github.com/hashcat/hashcat/pull/4090
• https://lists.debian.org/debian-perl/2025/05/msg00016.html
• https://lists.debian.org/debian-perl/2025/05/msg00017.html
• https://lists.debian.org/debian-perl/2025/05/msg00018.html
• https://github.com/mojolicious/mojo/pull/2252
• https://docs.mojolicious.org/Mojolicious/Guides/FAQ#What-does-Your-secret-passphrase-needs-to-be-changed-mean