CVE-2023-26130Public exploitNetwork attack vector

HTTP request header injection via unsanitized content types

Published May 30, 2023 · Updated Feb 13, 2025

CRLF injection in Yuji Hirose cpp-httplib before 0.12.4 allows remote attackers to inject HTTP request headers through content types. The Patch, Post, Put, and Delete client paths inserted caller-supplied content-type strings directly into the request header map instead of using set_header validation. Reachability requires an embedding application to place untrusted data in that API argument; injected CRLF sequences create attacker-chosen headers and alter downstream request handling.

CVSS severity8.8
High
EPSS probability1.14%
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 Yuji Hirose cpp-httplib before 0.12.4 allows remote attackers to inject HTTP request headers through content types. The Patch, Post, Put, and Delete client paths inserted caller-supplied content-type strings directly into the request header map instead of using set_header validation. Reachability requires an embedding application to place untrusted data in that API argument; injected CRLF sequences create attacker-chosen headers and alter downstream request handling.

The record

CVE
CVE-2023-26130
Published
May 30, 2023
Updated
Feb 13, 2025
Vendor
Yuji Hirose
Product
cpp-httplib
Classifications
CWE-77, CWE-74, CWE-93
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 30, 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=0 <0.12.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Yuji Hirose · cpp-httplibversion=0 <0.12.4

Published CVSS scores

7.5UbuntuCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
7.5SnykCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
8.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

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-77Improper Neutralization of Special Elements used in a Command ('Command Injection')
CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
CWE-93Improper Neutralization of CRLF Sequences ('CRLF Injection')

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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