CVE-2026-79770: Inefficient Regular Expression Complexity in sparklemotion nokogiri
Description
Nokogiri versions before 1.19.3 contain regular expression denial of service vulnerabilities in the CSS selector tokenizer affecting string-literal and identifier tokenization. Attackers can inject adversarial CSS selectors into methods like Node#css, Node#at_css, and Searchable#search to cause exponential regex backtracking and denial of service.
CVSS v4.0
Score 8.7high
Affected software
sparklemotion
nokogiri
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-79770 describes a ReDoS vulnerability in the Nokogiri library's CSS selector tokenizer affecting versions prior to 1.19.3. The flaw lies in inefficient regular expression handling during string-literal and identifier tokenization. Attackers can exploit this by injecting adversarial CSS selectors into Nokogiri methods that process CSS selectors, triggering exponential backtracking in regex evaluation and causing denial of service conditions.
Potential Impact
Successful exploitation results in denial of service by causing the Nokogiri process to consume excessive CPU resources due to exponential regex backtracking. This can disrupt applications relying on Nokogiri for CSS selector parsing, potentially leading to service unavailability.
Mitigation Recommendations
Upgrade Nokogiri to version 1.19.3 or later, where this vulnerability has been addressed. Patch status is confirmed by the affectedVersions data indicating versions before 1.19.3 are vulnerable. No other mitigation is indicated.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-08-25T14:29:43.528Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a8dba55acd9273b4965b682
Added to database: 08/25/2026, 15:52:53 UTC
Last enriched: 09/17/2026, 23:43:56 UTC
Last updated: 10/09/2026, 06:48:19 UTC
Views: 42
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