What is the CVSS score of CVE-2020-28327?

CVE-2020-28327 has a CVSS 3.1 base score of 5.3 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H. EPSS exploitation probability: 2.0%.

Is there a public PoC exploit available for CVE-2020-28327?

Yes, a public proof-of-concept exploit is available for CVE-2020-28327. Prioritise patching immediately. EPSS: 2.0%.

Is there a patch available for CVE-2020-28327?

Yes, a patch is available for CVE-2020-28327. Update the affected software to the latest version immediately.

Certified Asterisk CVE-2020-28327

MEDIUM

Improper Resource Shutdown or Release (CWE-404)

2020-11-06 cve@mitre.org

Denial Of Service Certified Asterisk Asterisk

5.3

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

5.3 MEDIUM

AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Attack Vector

Network

Attack Complexity

High

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Lifecycle Timeline

CVE Published

Nov 06, 2020 - 19:15 nvd

MEDIUM 5.3

DescriptionNVD

A res_pjsip_session crash was discovered in Asterisk Open Source 13.x before 13.37.1, 16.x before 16.14.1, 17.x before 17.8.1, and 18.x before 18.0.1. and Certified Asterisk before 16.8-cert5. Upon receiving a new SIP Invite, Asterisk did not return the created dialog locked or referenced. This caused a gap between the creation of the dialog object, and its next use by the thread that created it. Depending on some off-nominal circumstances and timing, it was possible for another thread to free said dialog in this gap. Asterisk could then crash when the dialog object, or any of its dependent objects, were dereferenced or accessed next by the initial-creation thread. Note, however, that this crash can only occur when using a connection-oriented protocol (e.g., TCP or TLS, but not UDP) for SIP transport. Also, the remote client must be authenticated, or Asterisk must be configured for anonymous calling.

AnalysisAI

A res_pjsip_session crash was discovered in Asterisk Open Source 13.x before 13.37.1, 16.x before 16.14.1, 17.x before 17.8.1, and 18.x before 18.0.1. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable. Public exploit code available.

Technical ContextAI

This vulnerability is classified under CWE-404. A res_pjsip_session crash was discovered in Asterisk Open Source 13.x before 13.37.1, 16.x before 16.14.1, 17.x before 17.8.1, and 18.x before 18.0.1. and Certified Asterisk before 16.8-cert5. Upon receiving a new SIP Invite, Asterisk did not return the created dialog locked or referenced. This caused a gap between the creation of the dialog object, and its next use by the thread that created it. Depending on some off-nominal circumstances and timing, it was possible for another thread to free said dialog in this gap. Asterisk could then crash when the dialog object, or any of its dependent objects, were dereferenced or accessed next by the initial-creation thread. Note, however, that this crash can only occur when using a connection-oriented protocol (e.g., TCP or TLS, but not UDP) for SIP transport. Also, the remote client must be authenticated, or Asterisk must be configured for anonymous calling. Affected products include: Digium Certified Asterisk, Sangoma Asterisk. Version information: before 13.37.1.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.