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CVE-2017-8872: Xmlsoft Libxml2: Information disclosure

CVE-2017-8872 is rated critical with a CVSS v3.0 base score of 9.1 and affects Xmlsoft Libxml2. Per its scoring, it can be exploited over the network, without authentication, without any user interaction.

Vulnerability description

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.

Severity breakdown

CVSS v3.0 9.1: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

• Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
• Attack complexity: Low. No special conditions; the attack can be repeated reliably.
• Privileges required: None. No account or prior access is needed.
• User interaction: None. No action from any user is needed.
• Scope: Unchanged. Impact stays within the vulnerable component.
• Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
• Integrity impact: None. No loss of integrity.
• Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

CWE-125: Out-of-bounds Read

The product reads data past the end, or before the beginning, of the intended buffer.

Affected products

• Xmlsoft Libxml2: 2.9.4

References

• https://bugzilla.gnome.org/show_bug.cgi?id=775200
• https://lists.debian.org/debian-lts-announce/2020/09/msg00009.html