CVE-2026-23739 | Asterisk xml.c uses unsafe XML_PARSE_NOENT leading to potential XXE Injection

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, the ast_xml_open() function in xml.c parses XML documents using libxml with unsafe parsing options that enable entity expansion and XInclude processing. Specifically, it invokes xmlReadFile() with the XML_PARSE_NOENT flag and later processes XIncludes via xmlXIncludeProcess().If any untrusted or user-supplied XML file is passed to this function, it can allow an attacker to trigger XML External Entity (XXE) or XInclude-based local file disclosure, potentially exposing sensitive files from the host system. This can also be triggered in other cases in which the user is able to supply input in xml format that triggers the asterisk process to parse it. This issue has been patched in versions 20.7-cert9, 20.18.2, 21.12.1, 22.8.2, and 23.2.2.

Published: 2026-02-06 Last update: 2026-02-18 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-23739 is rated Low Risk (14.1/100): CVSS Low severity, with low exploitation likelihood (EPSS 0.06%). Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-23739

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-15 0.05% 0.06% +0.01%
2 2026-04-02 0.10% 0.05% -0.05%
3 2026-02-07 — 0.10% —

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-23739

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
2.0 3.1 LOW
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 0.5 1.4 [email protected]
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 3.6 [email protected]

Weakness enumeration for CVE-2026-23739

OS Trackers for CVE-2026-23739

vendor priority summary link
alpine — CVE-2026-23739: 1 source package rows (asterisk); 101 state rows across 6 repos (3.19-main, 3.20-main, 3.21-main, 3.22-main, 3.23-main, edge-main); fixed 0, open 101. https://security.alpinelinux.org/vuln/CVE-2026-23739
debian unimportant CVE-2026-23739 unimportant priority: Debian including 1 source packages (asterisk), 2 status rows across 2 suites (bullseye, sid): resolved 2. https://security-tracker.debian.org/tracker/CVE-2026-23739
redhat low — https://access.redhat.com/security/cve/CVE-2026-23739
ubuntu medium CVE-2026-23739 medium priority: Ubuntu including 1 source packages (asterisk), 7 status rows across 7 suites (bionic, focal, jammy, noble, questing, upstream, xenial): needs-triage 7. https://ubuntu.com/security/CVE-2026-23739

Affected software / configurations for CVE-2026-23739

Vendor Product Version Raw CPE
sangoma asterisk < 20.18.2 cpe:2.3:a:sangoma:asterisk:*:*:*:*:*:*:*:*
sangoma asterisk >= 21.0.0, < 21.12.1 cpe:2.3:a:sangoma:asterisk:*:*:*:*:*:*:*:*
sangoma asterisk >= 22.0.0, < 22.8.2 cpe:2.3:a:sangoma:asterisk:*:*:*:*:*:*:*:*
sangoma asterisk >= 23.0.0, < 23.2.2 cpe:2.3:a:sangoma:asterisk:*:*:*:*:*:*:*:*
sangoma certified_asterisk <= 18.9 cpe:2.3:a:sangoma:certified_asterisk:*:*:*:*:*:*:*:*
sangoma certified_asterisk 20.7 cpe:2.3:a:sangoma:certified_asterisk:20.7:cert1:*:*:*:*:*:*
sangoma certified_asterisk 20.7 cpe:2.3:a:sangoma:certified_asterisk:20.7:cert1-rc1:*:*:*:*:*:*
sangoma certified_asterisk 20.7 cpe:2.3:a:sangoma:certified_asterisk:20.7:cert1-rc2:*:*:*:*:*:*
sangoma certified_asterisk 20.7 cpe:2.3:a:sangoma:certified_asterisk:20.7:cert2:*:*:*:*:*:*
sangoma certified_asterisk 20.7 cpe:2.3:a:sangoma:certified_asterisk:20.7:cert3:*:*:*:*:*:*
sangoma certified_asterisk 20.7 cpe:2.3:a:sangoma:certified_asterisk:20.7:cert4:*:*:*:*:*:*
sangoma certified_asterisk 20.7 cpe:2.3:a:sangoma:certified_asterisk:20.7:cert5:*:*:*:*:*:*
sangoma certified_asterisk 20.7 cpe:2.3:a:sangoma:certified_asterisk:20.7:cert6:*:*:*:*:*:*
sangoma certified_asterisk 20.7 cpe:2.3:a:sangoma:certified_asterisk:20.7:cert7:*:*:*:*:*:*
sangoma certified_asterisk 20.7 cpe:2.3:a:sangoma:certified_asterisk:20.7:cert8:*:*:*:*:*:*

References for CVE-2026-23739

cvelogic Threat Intelligence