Asterisk PBX up to 23.2.1 Endpoint http.c ast_str_append cross site scripting

CVSS Meta Temp Score
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CTI Interest Score
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4.3$0-$5k0.00

Summaryinfo

A vulnerability categorized as problematic has been discovered in Asterisk PBX up to 20.7-cert8/20.18.1/21.12.0/22.8.1/23.2.1. This impacts the function ast_str_append of the file http.c of the component Endpoint. Executing a manipulation can lead to cross site scripting. This vulnerability is handled as CVE-2026-23738. The attack can only be done within the local network. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Asterisk PBX up to 20.7-cert8/20.18.1/21.12.0/22.8.1/23.2.1. It has been declared as problematic. This vulnerability affects the function ast_str_append of the file http.c of the component Endpoint. The manipulation with an unknown input leads to a cross site scripting vulnerability. The CWE definition for the vulnerability is CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. As an impact it is known to affect integrity. CVE summarizes:

Asterisk is an open source private branch exchange and telephony toolkit. Prior to versions 20.7-cert9, 20.18.2, 21.12.1, 22.8.2, and 23.2.2, user supplied/control values for Cookies and any GET variable query Parameter are directly interpolated into the HTML of the page using ast_str_append. The endpoint at GET /httpstatus is the potential vulnerable endpoint relating to asterisk/main /http.c. This issue has been patched in versions 20.7-cert9, 20.18.2, 21.12.1, 22.8.2, and 23.2.2.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-23738 since 01/15/2026. The exploitation appears to be easy. The attack can only be done within the local network. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1059.007.

The vulnerability scanner Nessus provides a plugin with the ID 298281 (Linux Distros Unpatched Vulnerability : CVE-2026-23738), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 20.7-cert9, 20.18.2, 21.12.1, 22.8.2 or 23.2.2 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (298281) and CERT Bund (WID-SEC-2026-0327). Once again VulDB remains the best source for vulnerability data.

Affected

  • Open Source Asterisk

Productinfo

Type

Vendor

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.4
VulDB Meta Temp Score: 4.3

VulDB Base Score: 3.5
VulDB Temp Score: 3.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 6.1
NVD Vector: 🔒

CNA Base Score: 3.5
CNA Vector (GitHub_M): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Cross site scripting
CWE: CWE-79 / CWE-94 / CWE-74
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 298281
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-23738

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: PBX 20.7-cert9/20.18.2/21.12.1/22.8.2/23.2.2

Timelineinfo

01/15/2026 CVE reserved
02/06/2026 +22 days Advisory disclosed
02/06/2026 +0 days VulDB entry created
02/19/2026 +12 days VulDB entry last update

Sourcesinfo

Advisory: GHSA-v6hp-wh3r-cwxh
Status: Confirmed

CVE: CVE-2026-23738 (🔒)
GCVE (CVE): GCVE-0-2026-23738
GCVE (VulDB): GCVE-100-344716
CERT Bund: WID-SEC-2026-0327 - Asterisk: Mehrere Schwachstellen

Entryinfo

Created: 02/06/2026 21:20
Updated: 02/19/2026 00:37
Changes: 02/06/2026 21:20 (68), 02/07/2026 05:14 (7), 02/07/2026 11:50 (2), 02/19/2026 00:37 (11)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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