CVE-2023-41834Network attack vector

HTTP response splitting via unsanitized Netty headers

Published Sep 19, 2023 · Updated Feb 13, 2025

HTTP response splitting in Apache Flink Stateful Functions 3.1.0 through 3.2.0 allows remote attackers to inject headers via crafted HTTP requests. NettyRequestReplyHandler constructed HTTP headers without rejecting CR/LF characters, allowing attacker-controlled input to create additional header lines. Exploitation requires a crafted request to reach that path; the resulting response can carry phishing content or script.

CVSS severity6.1
Medium
EPSS probability1.61%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

HTTP response splitting in Apache Flink Stateful Functions 3.1.0 through 3.2.0 allows remote attackers to inject headers via crafted HTTP requests. NettyRequestReplyHandler constructed HTTP headers without rejecting CR/LF characters, allowing attacker-controlled input to create additional header lines. Exploitation requires a crafted request to reach that path; the resulting response can carry phishing content or script.

The record

CVE
CVE-2023-41834
Published
Sep 19, 2023
Updated
Feb 13, 2025
Vendor
The Apache Software Foundation
Product
Apache Flink Stateful Functions
Classifications
CWE-113, CWE-74, T1056.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 19, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 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=3.1.0 <=3.2.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Flink Stateful Functionsversion=3.1.0 <=3.2.0

Published CVSS scores

6.1National Institute of Standards and TechnologyCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A: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 exploitUnconfirmed

Weakness, pattern, technique

CWE-113Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')
CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
T1056.003Input Capture: Web Portal Capture

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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