How severe is CVE-2026-57436?

CVE-2026-57436 has a CVSS 3.x base score of 5.3, rated medium 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 low.

Is CVE-2026-57436 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-57436?

CVE-2026-57436 affects Nokogiri. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-57436?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-57436 have an EU (EUVD) identifier?

Yes. CVE-2026-57436 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-39427.

When was CVE-2026-57436 published?

CVE-2026-57436 was published on 2026-06-25 and last updated on 2026-06-26.

CVE-2026-57436

CVE-2026-57436 is a medium-severity vulnerability in Nokogiri with a CVSS 3.x base score of 5.3. 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-416.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v4: 1.7
EPSS exploit prediction: 0% (23rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-39427
Weakness: CWE-416
Affected product: Nokogiri
Published: 2026-06-25
Last modified: 2026-06-26

Description

Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, Nokogiri::XML::Document#root= validated only that the new root was a Nokogiri::XML::Node, allowing a DTD node to be set as the document root. The result is a heap use-after-free during garbage collection or finalization, leading to an invalid memory read or potentially a segfault. This vulnerability is fixed in 1.19.4.

Frequently asked questions

What is CVE-2026-57436?: Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, Nokogiri::XML::Document#root= validated only that the new root was a Nokogiri::XML::Node, allowing a DTD node to be set as the document root. The result is a heap use-after-free during garbage collection or finalization, leading to an invalid memory read or potentially a segfault. This vulnerability is fixed in 1.19.4.
How severe is CVE-2026-57436?: CVE-2026-57436 has a CVSS 3.x base score of 5.3, rated medium 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 low.
Is CVE-2026-57436 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-57436?: CVE-2026-57436 affects Nokogiri. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-57436?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-57436 have an EU (EUVD) identifier?: Yes. CVE-2026-57436 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-39427.
When was CVE-2026-57436 published?: CVE-2026-57436 was published on 2026-06-25 and last updated on 2026-06-26.

References

https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-wjv4-x9w8-wm3h

Affected products (1)

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

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