CVE-2025-57767: Asterisk can crash from a specifically malformed Authorization header in an incoming SIP request

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-08-28 · updated 2026-06-17
Weakness: CWE-253

Description

Asterisk is an open source private branch exchange and telephony toolkit. Prior to versions 20.15.2, 21.10.2, and 22.5.2, if a SIP request is received with an Authorization header that contains a realm that wasn't in a previous 401 response's WWW-Authenticate header, or an Authorization header with an incorrect realm was received without a previous 401 response being sent, the get_authorization_header() function in res_pjsip_authenticator_digest will return a NULL. This wasn't being checked before attempting to get the digest algorithm from the header which causes a SEGV. This issue has been patched in versions 20.15.2, 21.10.2, and 22.5.2. There are no workarounds.

Affected products

asterisk: before 20.15.2; from 21.0.0 before 21.10.2; from 22.0.0 before 22.5.2 — fixed in 20.15.2, 21.10.2, 22.5.2

How to fix

Upgrade to a fixed version: asterisk 20.15.2, 21.10.2, 22.5.2. Check the vendor advisory for mitigations.

References

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