Vulnerability identifier: #VU79797

Vulnerability risk: Medium

CVSSv3.1: 5.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2023-32731

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
gRPC
Server applications / Frameworks for developing and running applications

Vendor:

Description

The vulnerability allows a remote attacker to gain access to sensitive information.

The vulnerability exists due to insufficient validation of user-supplied input when parsing HTTP2 requests. When gRPC HTTP2 stack raised a header size exceeded error, it skipped parsing the rest of the HPACK frame. This caused any HPACK table mutations to also be skipped, resulting in a desynchronization of HPACK tables between sender and receiver. This could lead to requests from the proxy being interpreted as containing headers from different proxy clients, leading to an information leak that can be used for privilege escalation or data exfiltration.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

---

External links
http://github.com/grpc/grpc/pull/32309
http://github.com/grpc/grpc/pull/33005

---

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.