dbcve.org
Libxml2Framework / library · Xmlsoft

CVE-2017-8872

CRITICAL · 9.1 CVSS v3.1 Published 2017-05-10
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
The htmlParseTryOrFinish function in HTMLparser.c in libxml2 2.9.4 allows attackers to cause a denial of service (buffer over-read) or information disclosure.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

A buffer over-read vulnerability exists in the htmlParseTryOrFinish function in HTMLparser.c of libxml2 version 2.9.4. When parsing specially crafted HTML input, the parser reads beyond allocated buffer boundaries, potentially causing a denial of service through application crashes or enabling unauthorized information disclosure by exposing sensitive memory contents.

MitigationUpgrade libxml2 to a patched version. If immediate upgrade is not feasible, implement strict input validation on all HTML content before passing to libxml2 parsers, and deploy network-level controls to restrict untrusted HTML inputs.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Libxml2Framework / library
Affected:= 2.9.4

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed libxml2 version
    Run 'xml2-config --version' or check the library file with 'dpkg -l | grep libxml2' (Debian/Ubuntu), 'rpm -qa | grep libxml2' (RHEL/CentOS), or 'pkg-config --modversion libxml-2.0'
    Affected if The version reported is exactly 2.9.4
  2. Confirm libxml2 library file version
    Check the actual shared library file directly: 'ls -l /usr/lib/x86_64-linux-gnu/libxml2.so*' or 'ldconfig -p | grep libxml2' to locate the library, then examine its version metadata
    Affected if The library file version is exactly 2.9.4
  3. Identify applications using libxml2 HTML parser
    Search codebase or running processes for calls to htmlParseDoc, htmlReadDoc, htmlReadFile, or similar html* parsing functions from the libxml2 API
    Affected if Any application code calls libxml2 HTML parsing functions and uses libxml2 version 2.9.4
  4. Determine HTML input source trust level
    Audit where HTML input originates: check if it comes from user-uploaded files, web requests, remote APIs, or other untrusted sources versus only trusted local files
    Affected if HTML content from untrusted or remote sources is being parsed by the vulnerable libxml2 version

You are affected if libxml2 version 2.9.4 is installed AND your application or system parses HTML content (especially from untrusted sources) using the libxml2 library.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade libxml2 to a patched version. If immediate upgrade is not feasible, implement strict input validation on all HTML content before passing to libxml2 parsers, and deploy network-level controls to restrict untrusted HTML inputs.

Recommended fix High confidence

libxml2 2.9.5 or later (e.g., latest stable 2.9.x such as 2.9.14)

  1. 1. Identify the current libxml2 version in your environment by running `xml2-config --version` or checking your package manager.
  2. 2. If running libxml2 2.9.4, plan for upgrade to libxml2 2.9.5 or later.
  3. 3. For source compilation: download libxml2 2.9.5 or newer from https://download.gnome.org/sources/libxml2/ (e.g., 2.9.14 or latest stable).
  4. 4. Extract the source, run `./configure`, `make`, and `make install` as appropriate for your system.
  5. 5. For package managers: update via your distribution's package manager (e.g., `apt-get update && apt-get install libxml2` on Debian/Ubuntu, or `yum update libxml2` on RHEL/CentOS).
  6. 6. Verify the upgrade was successful by running `xml2-config --version` again to confirm version 2.9.5 or later is installed.
  7. 7. Restart any services that use libxml2 to ensure they load the updated library.
  8. 8. Test that your XML/HTML parsing functionality still works correctly with the new library.
Caveat Minor: Ensure any application-specific libxml2 API usage remains compatible; most applications work without changes. Verify no regression in XML/HTML parsing behavior.

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Libxml2 Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2017-8872 in production — separate from our analysis above.

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What belongs here
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  • Version or environment caveats, and links to real fixes
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