golang.org/x/net/http2/h2c: Inconsistent Interpretation of HTTP Requests
CVE-2022-41721 is a high-severity inconsistent interpretation of HTTP requests vulnerability in golang.org/x/net/http2/h2c from Golang.org/x/net, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 0.1.1-0.20221104162952-702349b0e862 as the first without the flaw, so updating golang.org/x/net/http2/h2c to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 1.88% chance of exploitation within 30 days, higher than 80% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update golang.org/x/net/http2/h2c to 0.1.1-0.20221104162952-702349b0e862 or a later version.
- Update H2c to 2022-11-04 or a later version.
- Read the advisory on go.dev for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Golang.org/x/net | golang.org/x/net/http2/h2c | 0.0.0-20220524220425-1d687d428aca up to, but not including, 0.1.1-0.20221104162952-702349b0e862 | 0.1.1-0.20221104162952-702349b0e862 |
| Go | H2c | before 2022-11-04 | 2022-11-04 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | NVD |
| CVSS 3.1 | 7.5 | High | CISA (ADP) |
Official description
A request smuggling attack is possible when using MaxBytesHandler. When using MaxBytesHandler, the body of an HTTP request is not fully consumed. When the server attempts to read HTTP2 frames from the connection, it will instead be reading the body of the HTTP request, which could be attacker-manipulated to represent arbitrary HTTP2 requests.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: 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.
How developers prevent this class of flaw
- Use a web server that employs a strict HTTP parsing procedure, such as Apache.
- Terminate the client session after each request.
More Inconsistent Interpretation of HTTP Requests vulnerabilities (CWE-444)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- go.dev/cl/447396
- go.dev/issue/56352Exploit, Issue Tracking
- pkg.go.dev/vuln/GO-2023-1495
Other references
Recent Inconsistent Interpretation of HTTP Requests vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
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