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CVE-2016-7835: Dena H2o: Use after free

CVE-2016-7835 is rated critical with a CVSS v3.0 base score of 9.1 and affects Dena H2o. Per its scoring, it can be exploited over the network, without authentication, without any user interaction.

Vulnerability description

Use-after-free vulnerability in H2O allows remote attackers to cause a denial-of-service (DoS) or obtain server certificate private keys and possibly other information.

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-416: Use After Free

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

Affected products

  • Dena H2o: up to and including 2.0.4
  • H2o Project: 2.1.0 beta3

References