CVE-2026-57201: Asterisk: Stack Buffer Overflow in H.323 ooTrace() via Unbounded vsprintf into Fixed 2048-byte Buffer

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-27 · updated 2026-10-30
Weakness: CWE-787

Description

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, a stack buffer overflow in the H.323 `ooTrace()` trace-logging function can occur when unbounded `vsprintf` writes into a fixed `2048-byte buffer`. A remote attacker may send a carefully crafted packet that causes the Asterisk process to crash. The `chan_ooh323` addon channel driver must be explicitly compiled and installed, which is not the default, and its port must be publicly reachable. 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.

Affected products

asterisk: before 20.20.1; from 21.0.0-pre1, < 21.12.3; from 22.0.0-pre1, < 22.10.1; from 23.0.0-pre1, < 23.4.1
asterisk certified-asterisk: before 20.7-cert11; from 22.8-cert1-pre1, < 22.8-cert3

References

Get alerted when CVE-2026-57201 or the next vulnerability affects your stack