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AsteriskApplication · Sangoma

CVE-2026-23741

HIGH · 8.8 CVSS v3.1 Published 2026-02-06
Fix available
A fix is available. Upgrade to 20.18.2 / 21.12.1 or later.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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 asterisk/contrib/scripts/ast_coredumper runs as root, as noted by the NOTES tag on line 689 of the ast_coredumper file. The script will source the contents of /etc/asterisk/ast_debug_tools.conf, which resides in a folder that is writeable by the asterisk user:group. Due to the /etc/asterisk/ast_debug_tools.conf file following bash semantics and it being loaded; an attacker with write permissions may add or modify the file such that when the root ast_coredumper is run; it would source and thereby execute arbitrary bash code found in the /etc/asterisk/ast_debug_tools.conf. This issue has been patched in versions 20.7-cert9, 20.18.2, 21.12.1, 22.8.2, and 23.2.2.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The ast_coredumper script runs as root but sources the configuration file /etc/asterisk/ast_debug_tools.conf, which is writable by the non-privileged asterisk user:group. An attacker with write access to this directory can inject arbitrary bash commands into the config file that will execute with root privileges when ast_coredumper is invoked, achieving privilege escalation.

MitigationUpdate Asterisk to versions 20.7-cert9, 20.18.2, 21.12.1, 22.8.2, or 23.2.2. Alternatively, restrict write permissions on /etc/asterisk/ast_debug_tools.conf to prevent modification by the asterisk user.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
AsteriskApplication
Affected:< 20.18.2>= 21.0.0, < 21.12.1>= 22.0.0, < 22.8.2>= 23.0.0, < 23.2.2
Certified AsteriskApplication
Affected:<= 18.9= 20.7

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify Asterisk version is affected
    Run 'asterisk -V' or 'asterisk --version' to get the installed version. Compare against affected ranges: < 20.18.2; >= 21.0.0, < 21.12.1; >= 22.0.0, < 22.8.2; >= 23.0.0, < 23.2.2; or for Certified: <= 18.9; = 20.7
    Affected if The installed version falls within any of the affected ranges listed in the CVE
  2. Confirm ast_coredumper script exists
    Check for the presence of ast_coredumper in typical locations: ls -la /usr/sbin/ast_coredumper or ls -la /usr/bin/ast_coredumper
    Affected if The script exists on the system and is executable by root
  3. Check config file permissions
    Run 'ls -la /etc/asterisk/ast_debug_tools.conf' to inspect ownership and permissions on the configuration file
    Affected if The file is owned by asterisk:asterisk or otherwise writable by the asterisk user (write bit set for user or group)
  4. Verify asterisk user has write access
    Use 'stat /etc/asterisk/ast_debug_tools.conf' or check group membership to confirm the asterisk user can modify this file
    Affected if The asterisk user or asterisk group has write permission (w) on the configuration file

You are affected if your Asterisk version is within the affected ranges AND the asterisk user has write access to /etc/asterisk/ast_debug_tools.conf, allowing injection of arbitrary commands that will execute as root when ast_coredumper runs.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 20.18.2 / 21.12.1 / 22.8.2 or later
Fixed in 20.18.221.12.122.8.2
Interim mitigation

Update Asterisk to versions 20.7-cert9, 20.18.2, 21.12.1, 22.8.2, or 23.2.2. Alternatively, restrict write permissions on /etc/asterisk/ast_debug_tools.conf to prevent modification by the asterisk user.

Recommended fix High confidence

Upgrade to Asterisk 20.18.2, 21.12.1, 22.8.2, or 23.2.2 (or Certified Asterisk 20.7-cert9)

  1. 1. Identify current Asterisk version by running `asterisk -V` or `asterisk -rx "core show version"`
  2. 2. Create a full backup of /etc/asterisk/ and any custom configurations
  3. 3. Stop the Asterisk service: `systemctl stop asterisk` or `/etc/init.d/asterisk stop`
  4. 4. Upgrade Asterisk using your distribution's package manager to one of the fixed versions: 20.18.2, 21.12.1, 22.8.2, or 23.2.2 (or 20.7-cert9 for Certified Asterisk)
  5. 5. Verify the new version is installed: `asterisk -V`
  6. 6. Start the Asterisk service: `systemctl start asterisk` or `/etc/init.d/asterisk start`
  7. 7. Verify Asterisk is running correctly: `asterisk -rx "core show version"`
Caveat Review Asterisk release notes for breaking changes between your current version and the target version before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Asterisk Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-23741 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
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