How severe is CVE-2026-79770?

CVE-2026-79770 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-79770 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (40th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-79770?

CVE-2026-79770 affects Nokogiri. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-79770?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2026-79770 published?

CVE-2026-79770 was published on 2026-08-25 and last updated on 2026-09-01.

CVE-2026-79770

CVE-2026-79770 is a high-severity vulnerability in Nokogiri with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1333.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 8.7
EPSS exploit prediction: 0% (40th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-1333
Affected product: Nokogiri
Published: 2026-08-25
Last modified: 2026-09-01

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.

Frequently asked questions

What is 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. 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.
How severe is CVE-2026-79770?: CVE-2026-79770 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-79770 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (40th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-79770?: CVE-2026-79770 affects Nokogiri. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-79770?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-79770 published?: CVE-2026-79770 was published on 2026-08-25 and last updated on 2026-09-01.

References

Affected products (1)

cpe:2.3:a:nokogiri:nokogiri:*:*:*:*:*:ruby:*:*

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