CVE Catalog

CVE-2026-35611

HighCVSS 7.5
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.36%

30th percentile - higher than 30% of all known CVEs

Summary

In Addressable's URI template implementation, certain templates generate regular expressions vulnerable to catastrophic backtracking. This affects templates using the * (explode) modifier and templates with multiple variables using the + or # operators. Matching a maliciously crafted URI can cause uncontrolled resource consumption and denial of service. The vulnerability is fixed in 2.9.0.

Risk Assessment

An attacker can send a maliciously crafted URI that triggers catastrophic backtracking, leading to uncontrolled resource consumption and denial of service. Applications processing URIs with vulnerable Addressable templates are at risk.

Recommendation

Update Addressable to version 2.9.0 or later. Review applications that use URI templates with the * modifier or multiple variables with + and # operators.

Related vulnerabilities

Original NVD description (English source)

Addressable is an alternative implementation to the URI implementation that is part of Ruby's standard library. From 2.3.0 to before 2.9.0, within the URI template implementation in Addressable, two classes of URI template generate regular expressions vulnerable to catastrophic backtracking. Templates using the * (explode) modifier with any expansion operator (e.g., {foo*}, {+var*}, {#var*}, {/var*}, {.var*}, {;var*}, {?var*}, {&var*}) generate patterns with nested unbounded quantifiers that are O(2^n) when matched against a maliciously crafted URI. Templates using multiple variables with the + or # operators (e.g., {+v1,v2,v3}) generate patterns with O(n^k) complexity due to the comma separator being within the matched character class, causing ambiguous backtracking across k variables. When matched against a maliciously crafted URI, this can result in catastrophic backtracking and uncontrolled resource consumption, leading to denial of service. This vulnerability is fixed in 2.9.0.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS