CVE-2026-26747
Monica Host Header Poisoning
Description
A Host Header Poisoning vulnerability exists in Monica 4.1.2 due to improper handling of the HTTP Host header in app/Providers/AppServiceProvider.php, combined with the default misconfiguration where the "app.force_url" is not set and default is "false". The application generates absolute URLs (such as those used in password reset emails) using the user-supplied Host header. This allows remote attackers to poison the password reset link sent to a victim,
INFO
Published Date :
Feb. 20, 2026, 5:25 p.m.
Last Modified :
Feb. 26, 2026, 2:42 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | CRITICAL | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Solution
- Set the "app.force_url" configuration option.
- Validate the HTTP Host header input.
- Update Monica to the latest version.
- Apply vendor security patches.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-26747.
| URL | Resource |
|---|---|
| https://github.com/hungnqdz/cve-research/blob/main/CVE-2026-26747.md | Exploit Vendor Advisory |
| https://github.com/monicahq/monica | Product |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-26747 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-26747
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-26747 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-26747 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Feb. 26, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:monicahq:monica:4.1.2:*:*:*:*:*:*:* Added Reference Type MITRE: https://github.com/hungnqdz/cve-research/blob/main/CVE-2026-26747.md Types: Exploit, Vendor Advisory Added Reference Type MITRE: https://github.com/monicahq/monica Types: Product -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Feb. 23, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N Added CWE CWE-644 -
New CVE Received by [email protected]
Feb. 20, 2026
Action Type Old Value New Value Added Description A Host Header Poisoning vulnerability exists in Monica 4.1.2 due to improper handling of the HTTP Host header in app/Providers/AppServiceProvider.php, combined with the default misconfiguration where the "app.force_url" is not set and default is "false". The application generates absolute URLs (such as those used in password reset emails) using the user-supplied Host header. This allows remote attackers to poison the password reset link sent to a victim, Added Reference https://github.com/hungnqdz/cve-research/blob/main/CVE-2026-26747.md Added Reference https://github.com/monicahq/monica