CVE-2017-17850 [High] | Input Validation Bypass in Asterisk

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.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-04-05	67.46%	29.96%	-37.50%
2	2025-10-21	72.18%	67.46%	-4.72%
3	2025-03-30	—	72.18%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-04-05

67.46%

29.96%

-37.50%

2025-10-21

72.18%

67.46%

-4.72%

2025-03-30

—

72.18%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
7.5	3.0	HIGH	`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	3.9	3.6	[email protected]
5.0	2.0	MEDIUM	`AV:N/AC:L/Au:N/C:N/I:N/A:P` Click to expand Access vector (AV:N) Can be exploited remotely over network reachability. Access complexity (AC:L) Exploitation conditions are straightforward and predictable. Authentication (AU:N) No authentication is required. Confidentiality impact (C:N) No confidentiality impact. Integrity impact (I:N) No integrity impact. Availability impact (A:P) Partial availability impact.	10.0	2.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

7.5

3.0

HIGH

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

3.9

3.6

[email protected]

5.0

2.0

MEDIUM

AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand

Access vector (AV:N): Can be exploited remotely over network reachability.
Access complexity (AC:L): Exploitation conditions are straightforward and predictable.
Authentication (AU:N): No authentication is required.
Confidentiality impact (C:N): No confidentiality impact.
Integrity impact (I:N): No integrity impact.
Availability impact (A:P): Partial availability impact.

10.0

2.9

[email protected]

OS Trackers for CVE-2017-17850

vendor	priority	summary	link
`debian`	not yet assigned	CVE-2017-17850 not yet assigned priority: Debian including 1 source packages (asterisk), 2 status rows across 2 suites (bullseye, sid): resolved 2.	https://security-tracker.debian.org/tracker/CVE-2017-17850
`gentoo`	normal	CVE-2017-17850: 1 GLSA(s) (201811-11), 1 atom(s) (net-misc/asterisk); latest impact normal.	https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2017-17850
`ubuntu`	low	CVE-2017-17850 low priority: Ubuntu including 1 source packages (asterisk), 21 status rows across 21 suites (artful, bionic, cosmic, disco, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial, zesty): not-affected 16, ignored 2, DNE 1, needed 1, released 1.	https://ubuntu.com/security/CVE-2017-17850

Affected software / configurations for CVE-2017-17850

Vendor	Product	Version	Raw CPE
digium	asterisk	>= 13.0.0, <= 13.18.4	cpe:2.3:a:digium:asterisk::::::::
digium	asterisk	>= 14.0.0, <= 14.7.4	cpe:2.3:a:digium:asterisk::::::::
digium	asterisk	>= 15.0.0, <= 15.1.4	cpe:2.3:a:digium:asterisk::::::::
digium	certified_asterisk	13.1.0	cpe:2.3:a:digium:certified_asterisk:13.1.0:::::::*
digium	certified_asterisk	13.1.0	cpe:2.3:a:digium:certified_asterisk:13.1.0:rc1::::::
digium	certified_asterisk	13.1.0	cpe:2.3:a:digium:certified_asterisk:13.1.0:rc2::::::
digium	certified_asterisk	13.8	cpe:2.3:a:digium:certified_asterisk:13.8:cert1::::::

References for CVE-2017-17850

URL	Tags
http://downloads.asterisk.org/pub/security/AST-2017-014.html	Vendor Advisory
http://www.securitytracker.com/id/1040056	Third Party Advisory VDB Entry
https://issues.asterisk.org/jira/browse/ASTERISK-27480	Issue Tracking Vendor Advisory
https://security.gentoo.org/glsa/201811-11

URL

CVE-2017-17850

Exploit prediction scoring system (EPSS) score for CVE-2017-17850

Common vulnerability scoring system (CVSS) metrics for CVE-2017-17850

Weakness enumeration for CVE-2017-17850

OS Trackers for CVE-2017-17850

Affected software / configurations for CVE-2017-17850

References for CVE-2017-17850