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GO-2026-4918 BIT-golang-2026-33814 CVE-2026-33814

Infinite loop in HTTP/2 transport when given bad SETTINGS_MAX_FRAME_SIZE in net/http/internal/http2 in golang.org/x/net

High Go
Severity
7.5 / 10
High · CVSS 3.1
Exploit chance (EPSS)
0.84%
Chance of exploitation in the next 30 days. Higher than 57.88% of scored vulnerabilities.
Known exploited
No
Not in CISA's catalog
Weakness
CWE-606 Unchecked Input for Loop Condition
CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop')
Fix
Available
2 packages have a fixed version

Description

When processing HTTP/2 SETTINGS frames, transport will enter an infinite loop of writing CONTINUATION frames if it receives a SETTINGS_MAX_FRAME_SIZE with a value of 0.

Affected versions

Go

PackageVulnerableFixed in
golang.org/x/net
< 0.53.0
0.53.0
stdlib
< 1.25.10
>= 1.26.0-0, < 1.26.3
1.25.10
1.26.3

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 → 0.53.0

go
go get golang.org/x/net@v0.53.0 && go mod tidy

stdlib Go → 1.26.3

go
go get stdlib@v1.26.3 && go mod tidy

Severity breakdown

CVSS 3.1 7.5

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

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

Weakness

CWE-606: Unchecked Input for Loop Condition

The product does not properly check inputs that are used for loop conditions, potentially leading to a denial of service or other consequences because of excessive looping.

How to prevent it
  • Implementation: Do not use user-controlled data for loop conditions.
  • Implementation: Perform input validation.

CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')

The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.

References

Advisories

Fixes and patches

Issue reports

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: Marwan Atia (marwansamir688@gmail.com)

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