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Debian LinuxOperating system · Debian

CVE-2019-13161

MEDIUM · 5.3 CVSS v3.1 Published 2019-07-12
Fix available
A fix is available. Upgrade to 13.27.1 / 15.7.3 or later.
See remediation →
59/100
Remediation priority · Elevated
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
An issue was discovered in Asterisk Open Source through 13.27.0, 14.x and 15.x through 15.7.2, and 16.x through 16.4.0, and Certified Asterisk through 13.21-cert3. A pointer dereference in chan_sip while handling SDP negotiation allows an attacker to crash Asterisk when handling an SDP answer to an outgoing T.38 re-invite. To exploit this vulnerability an attacker must cause the chan_sip module to send a T.38 re-invite request to them. Upon receipt, the attacker must send an SDP answer containing both a T.38 UDPTL stream and another media stream containing only a codec (which is not permitted according to the chan_sip configuration).

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

A pointer dereference vulnerability in the chan_sip module of Asterisk allows an attacker to crash the server during SDP negotiation. When Asterisk initiates a T.38 fax re-invite and receives a malformed SDP answer containing both a T.38 UDPTL stream and an additional media stream with only a codec (an invalid configuration), the module attempts to dereference a NULL pointer, causing a crash.

MitigationUpgrade Asterisk to versions beyond 13.27.0, 15.7.2, or 16.4.0 (or the relevant Certified Asterisk patched versions). If immediate patching is not possible, restrict SIP access to trusted endpoints to prevent untrusted parties from triggering T.38 re-invites.

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
Debian LinuxOperating system
Affected:= 8.0= 9.0
Certified AsteriskApplication
Affected:= 1.8.0.0= 1.8.1.0= 1.8.2.0= 1.8.3.0= 1.8.4.0= 1.8.5.0= 1.8.6.0= 1.8.7.0= 1.8.8.0= 1.8.9.0= 1.8.10.0= 1.8.11
AsteriskApplication
Affected:>= 13.0.0, < 13.27.1>= 15.0.0, < 15.7.3>= 16.0.0, < 16.4.1

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
High
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/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. Identify Asterisk installation and version
    Run 'asterisk -V' or 'asterisk -x "core show version"' to get the installed Asterisk version
    Affected if The version falls within any of these ranges: 13.0.0 to 13.27.0, 15.0.0 to 15.7.2, 16.0.0 to 16.4.0, or any 1.8.x Certified version listed
  2. Confirm chan_sip module is loaded
    Run 'module show like chan_sip' in the Asterisk CLI to check if the chan_sip module is currently loaded
    Affected if The chan_sip module is loaded and active
  3. Check T.38 fax (UDPTL) configuration
    Run 'sip show settings' in the Asterisk CLI and look for T.38 fax settings, or check sip.conf/extensions.conf for 't38pt_udptl' or 'faxdetect' configuration options
    Affected if T.38 fax support is enabled (t38pt_udptl is set to 'yes' or 'faxdetect' is enabled), allowing the vulnerable code path during T.38 re-invite negotiation

You are affected if you are running a vulnerable Asterisk version, have chan_sip loaded, and have T.38 fax support enabled, as this creates the conditions for the NULL pointer dereference during malformed SDP answer processing.

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.

From vendor data
Upgrade available Upgrade to 13.27.1 / 15.7.3 / 16.4.1 or later
Fixed in 13.27.115.7.316.4.1
Interim mitigation

Upgrade Asterisk to versions beyond 13.27.0, 15.7.2, or 16.4.0 (or the relevant Certified Asterisk patched versions). If immediate patching is not possible, restrict SIP access to trusted endpoints to prevent untrusted parties from triggering T.38 re-invites.

Fix this in Debian Linux Scoped from the published advisory
  • Consultation2.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,440
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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-2019-13161 in production — separate from our analysis above.

No notes yet

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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
  • No spam, self-promotion, credentials, or personal data