medium
5.3
CWE
285
Advisory Published
Updated

CVE-2016-9938

First published: Mon Dec 12 2016(Updated: )

An issue was discovered in Asterisk Open Source 11.x before 11.25.1, 13.x before 13.13.1, and 14.x before 14.2.1 and Certified Asterisk 11.x before 11.6-cert16 and 13.x before 13.8-cert4. The chan_sip channel driver has a liberal definition for whitespace when attempting to strip the content between a SIP header name and a colon character. Rather than following RFC 3261 and stripping only spaces and horizontal tabs, Asterisk treats any non-printable ASCII character as if it were whitespace. This means that headers such as Contact\x01: will be seen as a valid Contact header. This mostly does not pose a problem until Asterisk is placed in tandem with an authenticating SIP proxy. In such a case, a crafty combination of valid and invalid To headers can cause a proxy to allow an INVITE request into Asterisk without authentication since it believes the request is an in-dialog request. However, because of the bug described above, the request will look like an out-of-dialog request to Asterisk. Asterisk will then process the request as a new call. The result is that Asterisk can process calls from unvetted sources without any authentication. If you do not use a proxy for authentication, then this issue does not affect you. If your proxy is dialog-aware (meaning that the proxy keeps track of what dialogs are currently valid), then this issue does not affect you. If you use chan_pjsip instead of chan_sip, then this issue does not affect you.

Credit: cve@mitre.org

Affected SoftwareAffected VersionHow to fix
Asterisk=11.0.0
Asterisk=11.0.0-beta1
Asterisk=11.0.0-beta2
Asterisk=11.0.0-rc1
Asterisk=11.0.0-rc2
Asterisk=11.0.1
Asterisk=11.0.2
Asterisk=11.1.0
Asterisk=11.1.0-rc1
Asterisk=11.1.0-rc3
Asterisk=11.1.1
Asterisk=11.1.2
Asterisk=11.2.0
Asterisk=11.2.0-rc1
Asterisk=11.2.0-rc2
Asterisk=11.2.1
Asterisk=11.2.2
Asterisk=11.3.0
Asterisk=11.4.0
Asterisk=11.5.0
Asterisk=11.5.1
Asterisk=11.6.0
Asterisk=11.6.1
Asterisk=11.7.0
Asterisk=11.8.0
Asterisk=11.8.1
Asterisk=11.9.0
Asterisk=11.10.0
Asterisk=11.10.1
Asterisk=11.10.2
Asterisk=11.11.0
Asterisk=11.12.0
Asterisk=11.12.1
Asterisk=11.13.0
Asterisk=11.13.1
Asterisk=11.14.0
Asterisk=11.14.1
Asterisk=11.14.2
Asterisk=11.15.0
Asterisk=11.15.1
Asterisk=11.16.0
Asterisk=11.17.0
Asterisk=11.17.1
Asterisk=11.18.0
Asterisk=11.19.0
Asterisk=11.20.0
Asterisk=11.21.0
Asterisk=11.21.1
Asterisk=11.21.2
Asterisk=11.22.0
Asterisk=11.22.0-rc1
Asterisk=11.23.0
Asterisk=11.23.0-rc1
Asterisk=11.23.1
Asterisk=11.24.0
Asterisk=11.24.1
Asterisk=11.25.0
Asterisk=13.0.0
Asterisk=13.0.0-beta1
Asterisk=13.0.0-beta2
Asterisk=13.0.0-beta3
Asterisk=13.0.1
Asterisk=13.0.2
Asterisk=13.1.0
Asterisk=13.1.1
Asterisk=13.2.0
Asterisk=13.2.1
Asterisk=13.3.0
Asterisk=13.3.1
Asterisk=13.3.2
Asterisk=13.4.0
Asterisk=13.5.0
Asterisk=13.6.0
Asterisk=13.7.0
Asterisk=13.7.1
Asterisk=13.7.2
Asterisk=13.8.0
Asterisk=13.8.0-rc1
Asterisk=13.8.1
Asterisk=13.8.2
Asterisk=13.9.0
Asterisk=13.9.1
Asterisk=13.10.0
Asterisk=13.10.0-rc1
Asterisk=13.11.0
Asterisk=13.11.1
Asterisk=13.11.2
Asterisk=13.12.0
Asterisk=13.12.1
Asterisk=13.12.2
Asterisk=13.13.0
Asterisk=14.0.0
Asterisk=14.0.0-beta1
Asterisk=14.0.0-beta2
Asterisk=14.0.0-rc1
Asterisk=14.0.0-rc2
Asterisk=14.0.1
Asterisk=14.0.2
Asterisk=14.1.0
Asterisk=14.1.1
Asterisk=14.1.2
Asterisk=14.2.0
Digium Asterisk Appliance Developer Kit=11.0.0
Digium Asterisk Appliance Developer Kit=11.0.0-rc1
Digium Asterisk Appliance Developer Kit=11.0.0-rc2
Digium Asterisk Appliance Developer Kit=11.1.0
Digium Asterisk Appliance Developer Kit=11.1.0-rc1
Digium Asterisk Appliance Developer Kit=11.1.0-rc2
Digium Asterisk Appliance Developer Kit=11.1.0-rc3
Digium Asterisk Appliance Developer Kit=11.2.0
Digium Asterisk Appliance Developer Kit=11.2.0-rc1
Digium Asterisk Appliance Developer Kit=11.2.0-rc2
Digium Asterisk Appliance Developer Kit=11.3.0
Digium Asterisk Appliance Developer Kit=11.3.0-rc1
Digium Asterisk Appliance Developer Kit=11.3.0-rc2
Digium Asterisk Appliance Developer Kit=11.4.0
Digium Asterisk Appliance Developer Kit=11.4.0-rc1
Digium Asterisk Appliance Developer Kit=11.4.0-rc2
Digium Asterisk Appliance Developer Kit=11.4.0-rc3
Digium Asterisk Appliance Developer Kit=11.5.0
Digium Asterisk Appliance Developer Kit=11.5.0-rc1
Digium Asterisk Appliance Developer Kit=11.5.0-rc2
Digium Asterisk Appliance Developer Kit=11.6-cert1
Digium Asterisk Appliance Developer Kit=11.6-cert1
Digium Asterisk Appliance Developer Kit=11.6-cert1_rc1
Digium Asterisk Appliance Developer Kit=11.6-cert1_rc2
Digium Asterisk Appliance Developer Kit=11.6-cert10
Digium Asterisk Appliance Developer Kit=11.6-cert11
Digium Asterisk Appliance Developer Kit=11.6-cert12
Digium Asterisk Appliance Developer Kit=11.6-cert13
Digium Asterisk Appliance Developer Kit=11.6-cert14
Digium Asterisk Appliance Developer Kit=11.6-cert15
Digium Asterisk Appliance Developer Kit=11.6-cert2
Digium Asterisk Appliance Developer Kit=11.6-cert2
Digium Asterisk Appliance Developer Kit=11.6-cert3
Digium Asterisk Appliance Developer Kit=11.6-cert3
Digium Asterisk Appliance Developer Kit=11.6-cert4
Digium Asterisk Appliance Developer Kit=11.6-cert5
Digium Asterisk Appliance Developer Kit=11.6-cert6
Digium Asterisk Appliance Developer Kit=11.6-cert7
Digium Asterisk Appliance Developer Kit=11.6-cert8
Digium Asterisk Appliance Developer Kit=11.6-cert9
Digium Asterisk Appliance Developer Kit=11.6.0
Digium Asterisk Appliance Developer Kit=11.6.0
Digium Asterisk Appliance Developer Kit=11.6.0-rc1
Digium Asterisk Appliance Developer Kit=11.6.0-rc2

Never miss a vulnerability like this again

Sign up to SecAlerts for real-time vulnerability data matched to your software, aggregated from hundreds of sources.

Read MoreStart Free Trial

Reference Links

Frequently Asked Questions

  • What versions of Asterisk are affected by CVE-2016-9938?

    CVE-2016-9938 affects Asterisk versions 11.x prior to 11.25.1, 13.x prior to 13.13.1, and 14.x prior to 14.2.1.

  • What is the nature of the security issue described in CVE-2016-9938?

    CVE-2016-9938 is related to a vulnerability in the chan_sip channel driver that improperly handles whitespace, potentially allowing for unexpected behavior.

  • How serious is the CVE-2016-9938 vulnerability?

    CVE-2016-9938 has a moderate severity rating and may impact the security of affected Asterisk installations.

  • What steps should I take to mitigate CVE-2016-9938?

    To mitigate CVE-2016-9938, it is recommended to upgrade Asterisk to the latest patched versions, such as 11.25.1, 13.13.1, or 14.2.1.

  • Is there a specific patch available for CVE-2016-9938?

    Yes, patches for CVE-2016-9938 are included in the respective version updates for Asterisk, and upgrading is advised to apply the fix.

Company

Resources

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2025 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203