CVE-2026-2717Network attack vector

Administrator-level service interruption via unsanitized custom headers

Published Apr 22, 2026 · Updated Apr 22, 2026

CRLF injection in Dimitar Ivanov HTTP Headers 1.19.2 and earlier allows remote authenticated users to interrupt a WordPress site. The Custom Headers settings pass unneutralized header names and values to insert_with_markers(), which writes attacker-supplied newlines and Apache directives into .htaccess. Administrator-level access and the Apache .htaccess integration are required; malformed directives can produce parse errors that take the site offline.

CVSS severity5.5
Medium
EPSS probability0.47%
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 Dimitar Ivanov HTTP Headers 1.19.2 and earlier allows remote authenticated users to interrupt a WordPress site. The Custom Headers settings pass unneutralized header names and values to insert_with_markers(), which writes attacker-supplied newlines and Apache directives into .htaccess. Administrator-level access and the Apache .htaccess integration are required; malformed directives can produce parse errors that take the site offline.

The record

CVE
CVE-2026-2717
Published
Apr 22, 2026
Updated
Apr 22, 2026
Vendor
Dimitar Ivanov
Product
HTTP Headers
Classifications
CWE-93, T1499
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Apr 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 22, 2026Record 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 <=1.19.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Dimitar Ivanov · HTTP Headersversion=0 <=1.19.2

Published CVSS scores

5.5WordfenceCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-93Improper Neutralization of CRLF Sequences ('CRLF Injection')
T1499Endpoint Denial of Service

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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