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GHSA-4v7x-pqxf-cx7m BIT-golang-2023-45288 CVE-2023-45288 GO-2024-2687

net/http, x/net/http2: close connections when receiving too many headers

High Go
Severity
5.3 / 10
High · CVSS 3.1
Exploit chance (EPSS)
91.97%
Chance of exploitation in the next 30 days. Higher than 99.82% of scored vulnerabilities.
Known exploited
No
Not in CISA's catalog
Weakness
CWE-400 Uncontrolled Resource Consumption
Fix
Available
4 packages have a fixed version

Description

An attacker may cause an HTTP/2 endpoint to read arbitrary amounts of header data by sending an excessive number of CONTINUATION frames. Maintaining HPACK state requires parsing and processing all HEADERS and CONTINUATION frames on a connection. When a request's headers exceed MaxHeaderBytes, no memory is allocated to store the excess headers, but they are still parsed. This permits an attacker to cause an HTTP/2 endpoint to read arbitrary amounts of header data, all associated with a request which is going to be rejected. These headers can include Huffman-encoded data which is significantly more expensive for the receiver to decode than for an attacker to send. The fix sets a limit on the amount of excess header frames we will process before closing a connection.

Affected versions

Go

PackageVulnerableFixed in
golang.org/x/net
< 0.23.0
0.23.0
golang.org/x/net
< 0.23.0
0.23.0
golang.org/x/net/http2
< 0.23.0
0.23.0
golang.org/x/net/http2
< 0.23.0
0.23.0
net/http
< 1.21.9
1.21.9
net/http
>= 1.22.0-0, < 1.22.2
1.22.2
net/http
< 1.21.9
1.21.9
net/http
>= 1.22.0-0, < 1.22.2
1.22.2
stdlib
< 1.21.9
>= 1.22.0-0, < 1.22.2
1.21.9
1.22.2

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

golang.org/x/net Go → 0.23.0

go
go get golang.org/x/net@v0.23.0 && go mod tidy

golang.org/x/net/http2 Go → 0.23.0

go
go get golang.org/x/net/http2@v0.23.0 && go mod tidy

net/http Go → 1.21.9

go
go get net/http@v1.21.9 && go mod tidy

stdlib Go → 1.22.2

go
go get stdlib@v1.22.2 && go mod tidy

Severity breakdown

CVSS 3.1 5.3

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low

Weakness

CWE-400: Uncontrolled Resource Consumption

The product does not properly control the allocation and maintenance of a limited resource.

How to prevent it
  • Architecture and Design: Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place. The login application should be protected against DoS attacks as much as possible. Limiting the database access, perhaps by caching result sets, can help minimize the resources expended. To further limit the potential for a DoS attack, consider tracking the rate of requests received from users and blocking requests that exceed a defined rate threshold.
  • Architecture and Design: Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed. The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question. The second solution is simply difficult to effectively institute -- and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.
  • Architecture and Design: Ensure that protocols have specific limits of scale placed on them.
  • Implementation: Ensure that all failures in resource allocation place the system into a safe posture.

References

Advisories

Other links

Timeline

  1. Published
  2. Last updated by the source
  3. Latest EPSS score
AdvisorySeverityWhy it's related
GHSA-4374-p667-p6c8
HTTP/2 rapid reset can cause excessive work in net/http
High Known exploited Also affects golang.org/x/net
GHSA-qppj-fm5r-hxr3
HTTP/2 Stream Cancellation Attack
Medium Known exploited Also affects golang.org/x/net
CVE-2020-0601
Certificate validation bypass on Windows in crypto/x509
High Known exploited Also affects stdlib
GO-2026-6866
Check all ancestor namespace transitions when rendering raw text in html in golang.org/x/net
Not rated yet Also affects golang.org/x/net
GO-2026-6860
Avoid quadratic complexity when coalescing text nodes in html in golang.org/x/net
Not rated yet Also affects golang.org/x/net
RUSTSEC-2026-0382
Distrust compromised intermediate certificates in crypto/x509
Medium Also affects stdlib
GO-2026-6613
HTTP/1 server connection desynchronization after 2xx CONNECT response in net/http
High Also affects stdlib
GO-2026-6609
Lack of limit on size of parsed Range headers in net/http
High Also affects stdlib

Credits: Bartek Nowotarski (https://nowotarski.info/)

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