CVE-2026-57198: Asterisk: Possible RED T.140 Heap Buffer Overflow
Asterisk is an open source private branch exchange and telephony toolkit. In affected deployments, an authenticated attacker may cause a T.140 RED heap buffer overflow using carefully crafted packets, potentially allowing remote code execution or causing Asterisk to crash. The chansip channel driver must be installed and configured, and its textsupport option must be enabled; textsupport defaults to no. The chansip driver was deprecated in Asterisk 20 and completely removed in all later versions. Repository comparisons verify patch containment in Asterisk 20.20.1, 21.12.3, 22.10.1 and 23.4.1, and Certified Asterisk 20.7-cert11 and 22.8-cert3. The affected release-track scope remains unresolved: structured metadata includes later release tracks even though the advisory says the required chansip driver was removed there.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Asteriskto a version that resolves this vulnerability.Fixed in 20.20.1 - Upgrade
Upgrade
Asteriskto a version that resolves this vulnerability.Fixed in 21.12.3 - Upgrade
Upgrade
Asteriskto a version that resolves this vulnerability.Fixed in 22.10.1 - Upgrade
Upgrade
Asteriskto a version that resolves this vulnerability.Fixed in 23.4.1 - Upgrade
Upgrade
Certified Asteriskto a version that resolves this vulnerability.Fixed in 20.7-cert11 - Upgrade
Upgrade
Certified Asteriskto a version that resolves this vulnerability.Fixed in 22.8-cert3
Event History
Frequently Asked Questions
Which deployments are realistically exposed?
Exposure requires the deprecated chan_sip channel driver to be installed and configured, with its textsupport option enabled. Deployments that do not use chan_sip, or leave textsupport disabled, do not meet the stated prerequisites; textsupport defaults to no.
What access and input does an attacker need?
The issue is described as exploitable by an authenticated attacker who sends carefully crafted T.140 RED packets. Successful exploitation may result in remote code execution or an Asterisk crash.
Which versions are confirmed to contain the patch?
Patch containment is verified in Asterisk 20.20.1, 21.12.3, 22.10.1, and 23.4.1, plus Certified Asterisk 20.7-cert11 and 22.8-cert3.
What can be done if updating is not immediately possible?
Disable chan_sip textsupport, or remove/avoid use of the chan_sip driver where operationally feasible. This removes the stated configuration prerequisite for exploitation.
Does this apply to later Asterisk releases?
The advisory states that chan_sip was deprecated in Asterisk 20 and completely removed in later versions. However, the affected release-track scope is unresolved because structured metadata includes later tracks despite that removal.