Evidence-led vulnerability intelligence · 2026-10-27 22:47 IST

CVE-2026-57194

Asterisk is an open source private branch exchange and telephony toolkit. Prior to Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 20.7-cert11, 22.8-cert3, an out-of-bounds write in `chan_unistim` `DIALPAGE` digit handling can overflow the `phone_number` field and crash Asterisk when an attacker sends a carefully crafted incoming request packet. The `chan_unistim` module must be loaded and configured with a valid `UNISTIM UDP port` that the attacker can reach. The attacker must register as a configured `phone MAC`, or the deployment must have an equivalent `production/autoprovisioning` path that allows the client to reach the main page. This issue is fixed in Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 20.7-cert11, 22.8-cert3.

MEDIUM · 5.9

Executive briefing

The source record describes: Asterisk is an open source private branch exchange and telephony toolkit. Prior to Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 20.7-cert11, 22.8-cert3, an out-of-bounds write in `chan_unistim` `DIALPAGE` digit handling can overflow the `phone_number` field and crash Asterisk when an attacker sends a carefully crafted incoming request packet. The `chan_unistim` module must be loaded and configured with a valid `UNISTIM UDP port` that the attacker can reach. The attacker must register as a configured `phone MAC`, or the deployment must have an equivalent `production/autoprovisioning` path that allows the client to reach the main page. This issue is fixed in Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 20.7-cert11, 22.8-cert3. The practical risk depends on whether an affected product/version is present, reachable and configured in an exploitable way. Review the affected-product evidence and linked vendor advisories before assigning exposure status.

Assessment: Potential exposure only — validate the installed product, exact version, configuration and vendor applicability before treating an asset as confirmed vulnerable.

Evidence confidence: Limited Evidence-derived, not an exploitability verdict

Severity & attack characteristics

5.9 / 10 · 3.1

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

Attack vectorN

Attack complexityH

Privileges requiredN

User interactionN

ScopeU

Confidentiality impactN

Integrity impactN

Availability impactH

Technical explanation & impact

The technical mechanism is not expanded beyond the source description unless a referenced advisory supplies additional evidence. Read the linked vendor/CERT advisories for root-cause detail.

Potential impact must be interpreted from the published CVSS impact metrics and the affected component. A CVSS impact score is not proof that a particular asset is exploitable.

Weakness classification

CWE-787

Affected products and versions

NVD has not supplied machine-readable vulnerable CPE product/version entries for this CVE. This is an information gap, not proof that no products are affected. Check the vendor advisory references below.

Remediation & validation

Identify exposure by comparing the affected product and version ranges with your asset inventory, SBOM and externally exposed services.
Review the linked vendor security advisory or patch notes. Upgrade to a vendor-confirmed fixed release; do not infer a fixed version from the CVE description.
Until patched, consider restricting network access or disabling the affected feature where operationally safe. These are temporary controls, not a substitute for a vendor fix.
Validate the remediation with a version check and vulnerability rescan, then retain change evidence.

No fixed version is displayed unless it is explicitly established by a vendor advisory. Follow the vendor's release notes for exact product and branch applicability.

Vendor advisories, patches & exploit references

https://github.com/asterisk/asterisk/commit/430f423c84e4e32a462d907632b66c9793236e96 VENDOR security-advisories@github.com
https://github.com/asterisk/asterisk/commit/6da8e10c210d8e014c27c67235252e1dfc794446 VENDOR security-advisories@github.com
https://github.com/asterisk/asterisk/commit/6f414ec771eaa3318a4b2d28f70fa387196ae283 VENDOR security-advisories@github.com
https://github.com/asterisk/asterisk/commit/ce6e2233599b76bc30c33b4816b15609c8ddc8b6 VENDOR security-advisories@github.com
https://github.com/asterisk/asterisk/commit/d803b5370b05f39a6241b2556eb9894b02148e6a VENDOR security-advisories@github.com
https://github.com/asterisk/asterisk/commit/fc3a1cb3c386c962bfca8cd9d533d1390d4ad933 VENDOR security-advisories@github.com
https://github.com/asterisk/asterisk/commit/ff65e4b0867bee12cdcb3a6219b976ee7ee08963 VENDOR security-advisories@github.com
https://github.com/asterisk/asterisk/releases/tag/20.20.1 VENDOR security-advisories@github.com
https://github.com/asterisk/asterisk/releases/tag/21.12.3 VENDOR security-advisories@github.com
https://github.com/asterisk/asterisk/releases/tag/22.10.1 VENDOR security-advisories@github.com
https://github.com/asterisk/asterisk/releases/tag/23.4.1 VENDOR security-advisories@github.com
https://github.com/asterisk/asterisk/releases/tag/certified-20.7-cert11 VENDOR security-advisories@github.com
https://github.com/asterisk/asterisk/releases/tag/certified-22.8-cert3 VENDOR security-advisories@github.com
https://github.com/asterisk/asterisk/security/advisories/GHSA-3g56-cgrh-95p5 VENDOR security-advisories@github.com
https://github.com/asterisk/asterisk/tree/24.0.0-pre1 VENDOR security-advisories@github.com

Information gaps & confidence notes

These gaps indicate missing source data. CVE Watch does not fill them with guessed product, exploit or patch details.

NVD does not currently provide machine-readable vulnerable CPE product/version entries for this record.

Last enrichment: 2026-11-04T00:32:24+00:00 · Source last modified: 2026-11-02T20:17:45.757

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