Security readout for executives and security teams
Plain-English summary
Nokogiri versions before 1.18.8 bundle a vulnerable libxml2 release. Specially structured XML schema-validation inputs may cause an out-of-bounds memory read and disrupt the processing application. Risk is concentrated in services performing XML Schema validation, especially with attacker-controlled schemas or documents. The sources do not support data theft, code execution, or active exploitation.
Executive priority
Treat this as a targeted remediation priority rather than an organization-wide emergency. Quickly identify externally reachable XML-validation workloads and upgrade those first. The high supplied CVSS availability score warrants attention, but narrow trigger conditions, low upstream severity, and no cited exploitation evidence reduce immediate business urgency for systems without untrusted schema-validation inputs.
Technical view
The bundled libxml2 before 2.13.8 contains a heap buffer under-read in xmlSchemaIDCFillNodeTables within xmlschemas.c. Trigger conditions include untrusted schemas, or untrusted XML validated against trusted schemas using xsd:keyref with recursively defined types and additional identity constraints. The supplied CVSS 4.0 score is 8.7, although upstream and MITRE reportedly classify severity as low.
Likely exposure
Exposure is most likely where Ruby applications use Nokogiri before 1.18.8 for XML Schema validation and accept attacker-influenced schemas or XML documents. Applications that do not perform schema validation, or cannot receive untrusted validation inputs, have substantially lower practical exposure. The bundle does not establish which platforms or Nokogiri packaging variants are affected.
Exploitation context
The source bundle reports no CISA KEV listing and provides no evidence of active exploitation or a public exploit. Exploitation requires particular XML Schema validation behavior, narrowing practical reach. The documented consequence is an under-read with availability impact; the supplied evidence does not establish remote code execution, confidentiality loss, or integrity loss.
Researcher notes
CVE-2025-71346 describes Nokogiri's packaging of the libxml2 flaw tracked as CVE-2025-32415. Severity signals conflict: the bundle supplies CVSS 4.0 8.7 with high availability impact, while reporting low upstream and MITRE severity. Researchers should preserve that distinction and avoid inferring code execution. The affected-version array is ambiguous, but the narrative consistently states versions before 1.18.8.
Mitigation direction
- Upgrade Nokogiri to version 1.18.8 or later following the vendor advisory.
- Prioritize internet-facing services that validate attacker-controlled XML schemas or documents.
- Restrict untrusted XML Schema validation until affected dependencies are upgraded.
- Review vendor guidance for platform-specific package or deployment requirements.
Validation and detection
- Inventory deployed Nokogiri versions, including transitive dependencies and packaged production artifacts.
- Identify code paths invoking XML Schema validation through Nokogiri.
- Determine whether schemas or validated XML documents can be influenced by untrusted users.
- Review trusted schemas for xsd:keyref, recursive types, and additional identity constraints.
- Confirm rebuilt production artifacts contain Nokogiri 1.18.8 or later.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
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CWE-125: Exact CWE lookup
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Open ATT&CK lookupCVE-2025-71346 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.7 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
2 official scoresWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N——VulnCheckCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L1.41.4VulnCheckVulnerability scoring details
Base CVSS 4.0 score
8.7HighVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Base CVSS 3.1 score
2.9LowVector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- GitHub Security Advisory (GHSA-5w6v-399v-w3cc)CVE reference, VulnCheck · vendor-advisory
- VulnCheck Advisory: Nokogiri before 1.18.8 Heap Buffer Under-read via XML SchemaCVE reference, VulnCheck · third-party-advisory
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Out-of-bounds Read
Out-of-bounds Read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.