Is this vulnerability remotely exploitable?

Yes, in typical networked deployments where an attacker can influence HTTP responses handled by AIOHTTP, it can be remotely exploitable. The exact impact depends on how the application forwards or interprets malformed headers and whether intermediaries are involved.

What level of access does an attacker need to exploit this?

An attacker generally needs the ability to act as or affect an upstream HTTP endpoint or to tamper with traffic in transit (for example, as a malicious server, compromised upstream, or network-position adversary). Direct local access to the AIOHTTP process is not required if they can control the response stream.

What is the safest general fix pattern for developers?

Enforce strict header validation in all HTTP parsing paths: reject or sanitize any header containing control characters or null bytes, and rely on well-maintained, protocol-compliant parsing primitives rather than hand-rolled logic. Ensure that malformed input leads to a clear error and not to partial or ambiguous parsing.

Severity:

CRITICAL RISK

(9.1)

HTTP Response Splitting via Improper Header Validation (CWE-113) in AIOHTTP C Parser

CVE-2026-34520

Published:

Apr 1, 2026

Status:

Undergoing Analysis

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

NDV

Recent Vulnerabilities

CWE-77;CWE-78

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in Totolink A7100RU setGameSpeedCfg CGI Handler

Remote Code Execution on the Router

April 6, 2026

CWE-77;CWE-78

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in Totolink A7100RU setFirewallType Handler

Remote Code Execution on Router Firmware

April 6, 2026

Vulnerability Type

Category:

HTTP Response Splitting / Header Injection

CWE:

CWE-113

Impact:

HTTP Response Splitting and Header Injection

Severity:

CRITICAL RISK

(9.1)

CVSS Version:

3.1

Vulnerability Type

Category:

HTTP Response Splitting / Header Injection

CWE:

CWE-113

Impact:

HTTP Response Splitting and Header Injection

Severity:

CRITICAL RISK

(9.1)

CVSS Version:

3.1

Catch This CVE While Code Is Being Written

Detect vulnerable code directly in pull requests, so CVEs are fixed before merge.

Get Started

Ship clean & secure code faster

START 14 DAYS FREE TRIAL

BOOK A DEMO

Made with Love in San Francisco

355 Bryant St. San Francisco, CA 94107, USA

Ask AI for summary of CodeAnt

Made with Love in San Francisco

355 Bryant St. San Francisco, CA 94107, USA

Ask AI for summary of CodeAnt

Made with Love in San Francisco

355 Bryant St. San Francisco, CA 94107, USA

Ask AI for summary of CodeAnt

HTTP Response Splitting via Improper Header Validation (CWE-113) in AIOHTTP C Parser

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

Recent Vulnerabilities

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in Totolink A7100RU setGameSpeedCfg CGI Handler

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in Totolink A7100RU setFirewallType Handler

Vulnerability Type

Vulnerability Type

Vulnerability Type

Catch This CVE While Code Is Being Written

Ship clean & secure code faster

Product

Pricing

Company

Legal

Developers

Compare

Product

Pricing

Company

Legal

Developers

Compare

Product

Pricing

Company

Legal

Developers

Compare