CVE-2017-17850
HighSummary
An issue was discovered in Asterisk versions 13.18.4 and older, 14.7.4 and older, 15.1.4 and older, and 13.18-cert1 and older that causes a crash when processing certain SIP messages without a contact header. This issue occurs only when the PJSIP channel driver is used.
Risk Assessment
The risk to the organization is that unauthorized users could cause the Asterisk server to crash, leading to service availability interruptions. Enabling authentication mitigates this risk as it requires user authorization before reaching the crash point.
Recommendation
It is recommended to update Asterisk to the latest version to eliminate this vulnerability. Additionally, enabling authentication for SIP users can help minimize the risk.
Other vulnerabilities in Asterisk
See all- CVE-2017-14603High
In Asterisk 11.x before 11.25.3, 13.x before 13.17.2, and 14.x before 14.6.2, insufficient RTCP packet validation could allow reading stale buffer contents. When combined with the 'nat' and 'symmetric_rtp' options, this could allow redirecting where Asterisk sends the next RTCP report.
- CVE-2026-57203Medium
ast_loggrabber executes a Python script from the world-writable /tmp directory. An attacker already authorized to open a shell session on the Asterisk server may place a malicious script there and gain elevated privileges or execute code when an administrator runs ast_loggrabber with elevated privileges.
- CVE-2026-57199Low
app_sms.c copies externally controlled SMS lengths into fixed in-struct buffers without sufficient bounds checks, allowing an attacker to corrupt memory or crash Asterisk. The SMS dialplan application must be explicitly used and input not validated.
- CVE-2026-57192Medium
An out-of-bounds write in the Codec2 decoder caused by a floor/ceil sample-count mismatch leads to a heap buffer overflow. An authenticated attacker can exploit it by sending crafted Codec2 audio packets within an established call.
- CVE-2026-57191High
An unbounded sscanf in res_pjsip_pubsub when parsing the MWI NOTIFY Message-Account field may allow an unauthenticated attacker to send a crafted packet causing a stack buffer overflow and corrupting the transport, permanently disabling all SIP functionality until restart.
- CVE-2026-57190High
The PostgreSQL and TDS/MSSQL Channel Event Log backends cel_pgsql and cel_tds may permit arbitrary SQL execution when untrusted data is set in the CEL eventtype column by the CELGenUserEvent dialplan application. The backend must be loaded and configured, and CELGenUserEvent must be called without validating input.
- CVE-2026-57186High
The chan_ooh323 Q.931 party-number parser lacks the CVE-2022-37325 fix, which was never forward-ported from Asterisk 20 to later versions. Malformed Q.931 elements in an OOH323 request can crash Asterisk.
- CVE-2026-57200High
In Asterisk prior to 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 22.8-cert3, an authenticated attacker with read-only ARI permissions may, under certain conditions, perform write operations via REST-over-WebSocket. The authorization bypass enables arbitrary module path loading and conditional remote code execution.
- CVE-2026-57195High
In Asterisk prior to 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 20.7-cert11, 22.8-cert3, a NULL pointer dereference in the Asterisk Manager Interface (AMI) may allow an unauthenticated attacker to crash Asterisk when Digest Authentication is used via HTTP.
- CVE-2026-57202High
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 authenticated Asterisk REST Interface (ARI) attacker with read-only privileges may use setChannelVar to execute write dialplan functions, including FILE() writes, even when live_dangerously in asterisk.conf is set to no. The Asterisk HTTP web server must be enabled and reachable, and the attacker must already have valid read-only ARI credentials; HTTP is disabled by default and binds only to 127.0.0.1 by default even when enabled.
Original NVD description (English source)
An issue was discovered in Asterisk 13.18.4 and older, 14.7.4 and older, 15.1.4 and older, and 13.18-cert1 and older. A select set of SIP messages create a dialog in Asterisk. Those SIP messages must contain a contact header. For those messages, if the header was not present and the PJSIP channel driver was used, Asterisk would crash. The severity of this vulnerability is somewhat mitigated if authentication is enabled. If authentication is enabled, a user would have to first be authorized before reaching the crash point.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS

