CVE-2025-53094Public exploitNetwork attack vector

HTTP response manipulation via unsanitized header fields

Published Jun 27, 2025 · Updated Jun 27, 2025

CRLF injection in ESP32Async ESPAsyncWebServer 3.7.8 and earlier allows remote attackers to manipulate HTTP headers and responses. AsyncWebHeader splits a supplied header string at the first colon and serializes the resulting name and value without rejecting carriage returns or line feeds. Exploitation requires an application to pass attacker-controlled header data into this constructor; injected line breaks can add headers or split an HTTP response.

CVSS severity8.7
High
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

CRLF injection in ESP32Async ESPAsyncWebServer 3.7.8 and earlier allows remote attackers to manipulate HTTP headers and responses. AsyncWebHeader splits a supplied header string at the first colon and serializes the resulting name and value without rejecting carriage returns or line feeds. Exploitation requires an application to pass attacker-controlled header data into this constructor; injected line breaks can add headers or split an HTTP response.

The record

CVE
CVE-2025-53094
Published
Jun 27, 2025
Updated
Jun 27, 2025
Vendor
ESP32Async
Product
ESPAsyncWebServer
Classifications
CWE-113, CWE-93, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 27, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 27, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=<= 3.7.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ESP32Async · ESPAsyncWebServerversion=<= 3.7.8

Published CVSS scores

8.7GitHub CNACVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-113Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')
CWE-93Improper Neutralization of CRLF Sequences ('CRLF Injection')
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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