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CVE-2021-47996— Nokogiri before 1.11.4 Multiple Vulnerabilities via libxml2

Quick assessment

Affected
sparklemotion nokogiri
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Nokogiri 1.11.4 之前的版本（仅限 CRuby 实现，且在使用打包/内嵌的 libxml2 时）捆绑了 libxml2 2.9.10，该版本存在多个在 libxml2 2.9.12 中得到修复的安全漏洞，包括： xmlSchemaValidateStream 中的内存泄漏（CVE-2019-20388） xmlEncodeEntitiesInternal 中的全局缓冲区越界读取（CVE-2020-24977） 基于堆的缓冲区溢出（CVE-2021-3517） 越界读取（CVE-2021-3518） 处

CVSS 7.5 · High

Affected Version Matrix 2

VendorProduct Version RangeStatus
sparklemotion nokogiri < 1.11.4 affected
1.11.4 unaffected
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I. Basic Information for CVE-2021-47996

Vulnerability Information
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Vulnerability Title
Nokogiri before 1.11.4 Multiple Vulnerabilities via libxml2
Source: CVE Program / CVE List V5
Vulnerability Description
Nokogiri before 1.11.4 (CRuby implementation only, when the packaged/vendored libxml2 is used) bundles libxml2 2.9.10, which is affected by multiple vulnerabilities addressed in libxml2 2.9.12, including a memory leak in xmlSchemaValidateStream (CVE-2019-20388), a global buffer over-read in xmlEncodeEntitiesInternal (CVE-2020-24977), a heap-based buffer overflow (CVE-2021-3517), and an out-of-bounds read (CVE-2021-3518). Processing crafted XML documents may lead to denial of service, information disclosure, or memory corruption.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
内存缓冲区边界内操作的限制不恰当
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
sparklemotion nokogiri 0 ~ 1.11.4 -

II. Public POCs for CVE-2021-47996

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III. Intelligence Information for CVE-2021-47996

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Patches & Fixes for CVE-2021-47996 (8)

Vendor Advisories for CVE-2021-47996 (1)

Other References for CVE-2021-47996 (1)

Same Patch Batch · sparklemotion · 2026-08-25 · 14 CVEs total

CVE-2024-58378 9.8 CRITICAL Nokogiri before 1.16.2 Use-After-Free via xmlTextReader
CVE-2022-51000 9.8 CRITICAL Nokogiri before 1.13.2 Multiple Vulnerabilities via libxml2 libxslt
CVE-2025-71407 9.8 CRITICAL Nokogiri before 1.18.3 Stack Buffer Overflow and Use-After-Free
CVE-2022-50999 8.6 HIGH Nokogiri before 1.13.5 Integer Overflow via libxml2
CVE-2025-71406 7.8 HIGH Nokogiri before 1.18.4 Use-After-Free via libxslt
CVE-2023-54354 7.5 HIGH Nokogiri before 1.14.3 Null Pointer Dereference via libxml2
CVE-2026-79770 7.5 HIGH Nokogiri before 1.19.3 ReDoS via CSS selector tokenizer
CVE-2022-50998 7.5 HIGH Nokogiri before 1.13.9 Multiple Vulnerabilities via libxml2
CVE-2026-79769 5.5 MEDIUM Nokogiri before 1.19.4 Invalid Memory Read via initialize_copy_with_args
CVE-2026-79771 5.3 MEDIUM Nokogiri before 1.19.3 Memory Leak via XSLT Transform
CVE-2026-79772 5.3 MEDIUM Nokogiri before 1.19.1 Unchecked Return Value canonicalize
CVE-2025-71346 2.9 LOW Nokogiri before 1.18.8 Heap Buffer Under-read via XML Schema
CVE-2024-58377 Nokogiri before 1.16.5 libxml2 Dependency Update

IV. Related Vulnerabilities

Same product: nokogiri
Same vendor: sparklemotion
Same weakness: CWE-119

V. Comments for CVE-2021-47996

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