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GHSA-5prr-v3j2-97mh
No affected components available
Summary
Nokogiri::XML::NodeSet#[] (and its alias #slice) checked the requested index against the node set's bounds using a 32-bit-truncated copy of the index. A large negative index could pass the check and then be used at full width, reading outside the node set's storage. On CRuby this is an out-of-bounds read that typically crashes the process; on JRuby it is not memory-unsafe but returns an incorrect node.
Nokogiri 1.19.4 performs the bounds check against the full-width index.
Severity
The Nokogiri maintainers have evaluated this as medium severity.
Exploitation requires an application to pass an attacker-controlled integer to NodeSet#[]. The primary impact is a controlled crash (denial of service), with potential for memory disclosure on CRuby.
On JRuby, Nokogiri is not affected by this vulnerability.
Mitigation
Upgrade to Nokogiri 1.19.4 or later.
As a workaround, applications that index a NodeSet with externally-supplied integers can validate the index against node_set.length before use, or avoid passing untrusted values as an index.
Credit
This issue was responsibly reported by Zheng Yu from depthfirst.com.
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability.
Limited exploitation activity has been observed. Close monitoring and planned remediation are recommended.
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.
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