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CVE-2018-21245: Apsis Pound: Inconsistent Interpretation of HTTP Requests

CVE-2018-21245 is rated critical with a CVSS v3.1 base score of 9.1 and affects Apsis Pound. Per its scoring, it can be exploited over the network, without authentication, without any user interaction.

Vulnerability description

Pound before 2.8 allows HTTP request smuggling, a related issue to CVE-2016-10711.

Severity breakdown

CVSS v3.1 9.1: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

• 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: High. Total loss of integrity; data or system state can be fully modified.
• Availability impact: None. No effect on availability.

Underlying weakness

CWE-444: Inconsistent Interpretation of HTTP Requests

The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.

Affected products

• Apsis Pound: before 2.8

References

• https://admin.hostpoint.ch/pipermail/pound_apsis.ch/2018-May/000054.html
• https://bugs.gentoo.org/714084