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CVE-2021-43848 Detail

Current Description

h2o is an open source http server. In code prior to the `8c0eca3` commit h2o may attempt to access uninitialized memory. When receiving QUIC frames in certain order, HTTP/3 server-side implementation of h2o can be misguided to treat uninitialized memory as HTTP/3 frames that have been received. When h2o is used as a reverse proxy, an attacker can abuse this vulnerability to send internal state of h2o to backend servers controlled by the attacker or third party. Also, if there is an HTTP endpoint that reflects the traffic sent from the client, an attacker can use that reflector to obtain internal state of h2o. This internal state includes traffic of other connections in unencrypted form and TLS session tickets. This vulnerability exists in h2o server with HTTP/3 support, between commit 93af138 and d1f0f65. None of the released versions of h2o are affected by this vulnerability. There are no known workarounds. Users of unreleased versions of h2o using HTTP/3 are advised to upgrade immediately.


View Analysis Description

Severity



CVSS 3.x Severity and Metrics:

NIST CVSS score
NIST: NVD
Base Score:  5.9 MEDIUM
Vector:  CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Nist CVSS score does not match with CNA score
CNA:  GitHub, Inc.
Base Score:  7.4 HIGH
Vector:  CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H


NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: It is possible that the NVD CVSS may not match that of the CNA. The most common reason for this is that publicly available information does not provide sufficient detail or that information simply was not available at the time the CVSS vector string was assigned.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
https://github.com/h2o/h2o/commit/8c0eca3 Patch  Third Party Advisory 
https://github.com/h2o/h2o/security/advisories/GHSA-f9xw-j925-m4m4 Third Party Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-908 Use of Uninitialized Resource Provider acceptance level GitHub, Inc.  

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Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2021-43848
NVD Published Date:
02/01/2022
NVD Last Modified:
02/07/2022
Source:
GitHub, Inc.