dbcve.org
AsteriskApplication · Sangoma

CVE-2025-49832

MEDIUM · 6.5 CVSS v3.1 Published 2025-08-01
Fix available
A fix is available. Upgrade to 18.26.3 / 20.15.1 or later.
See remediation →
71/100
Remediation priority · Elevated
Public exploit 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. In versions up to and including 18.26.2, between 20.00.0 and 20.15.0, 20.7-cert6, 21.00.0, 22.00.0 through 22.5.0, there is a remote DoS and possible RCE condition in `asterisk/res/res_stir_shaken /verification.c` that can be exploited when an attacker can set an arbitrary Identity header, or STIR/SHAKEN is enabled, with verification set in the SIP profile associated with the endpoint to be attacked. This is fixed in versions 18.26.3, 20.7-cert6, 20.15.1, 21.10.1 and 22.5.1.

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
How this class of weakness works · CWE-476

The code follows a pointer that is null, crashing the process. An attacker who can reliably trigger it turns the crash into a denial of service. The fix is checking for null before use and handling the failure path gracefully.

General guidance for the null pointer dereference class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

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:< 18.26.3>= 20.0.0, < 20.15.1>= 21.0.0, < 21.10.1>= 22.0.0, < 22.5.1
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
None
Integrity
None
Availability
High

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

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 18.26.3 / 20.15.1 / 21.10.1 or later
Fixed in 18.26.320.15.121.10.1
Recommended fix High confidence

Upgrade to Asterisk 18.26.3, 20.15.1, 21.10.1, or 22.5.1 (standard) or Certified Asterisk 20.7-cert6 based on your current branch

  1. 1. Identify the currently installed Asterisk version using `asterisk -V` or `core show version`
  2. 2. Determine which branch you are on (Asterisk 18.x, 20.x, 21.x, 22.x, or Certified Asterisk 20.7)
  3. 3. Backup your Asterisk configuration directory (typically /etc/asterisk) and any custom scripts
  4. 4. Download the appropriate fixed version from downloads.asterisk.org: 18.26.3, 20.15.1, 21.10.1, or 22.5.1 for standard releases; 20.7-cert6 for Certified Asterisk
  5. 5. Compile and install the new version following standard Asterisk build procedures (./configure, make, make install)
  6. 6. Restart the Asterisk service: `systemctl restart asterisk` or `service asterisk restart`
  7. 7. Verify the upgrade succeeded and STIR/SHAKEN verification is functional using `module show like stir`
  8. 8. Test SIP endpoint registration and call flows to ensure normal operation
Caveat Standard Asterisk upgrades may introduce minor behavioral changes; review the CHANGES file in the new release for STIR/SHAKEN-related modifications

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

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $2,850. Get the upgrade done

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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-2025-49832 in production — separate from our analysis above.

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What belongs here
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  • Version or environment caveats, and links to real fixes
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