CVE-2026-79770
Nokogiri versions before 1.19.3 contain regular expression denial of service vulnerabilities in the CSS selector tokenizer affecting string-literal and identifier tokenization.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.28%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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 4.0
- 8.7 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.28% probability · 20th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-1333
- Affected
- nokogiri/nokogiri
- Source
- disclosure@vulncheck.com
References
- https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-c4rq-3m3g-8wgxMitigation, Vendor Advisory
- https://www.vulncheck.com/advisories/nokogiri-before-redos-via-css-selector-tokenizerThird Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.