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CVE-2023-49786· NVD / CVE Program· CNA GitHub_M

Asterisk susceptible to Denial of Service via DTLS Hello packets during call initiation

Noroxi assessment

Priority: Monitor (action score 25/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 5.2% (FIRST EPSS); higher than 92.5% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: asterisk (Alpine:v3.16) 18.20.2-r0; asterisk (Alpine:v3.19) 20.5.1-r0; asterisk (Debian:10) 1:16.28.0~dfsg-0+deb10u4.

Low priority for now. Upgrade to asterisk (Alpine:v3.16) 18.20.2-r0; asterisk (Alpine:v3.19) 20.5.1-r0; asterisk (Debian:10) 1:16.28.0~dfsg-0+deb10u4 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Asterisk is an open source private branch exchange and telephony toolkit. In Asterisk prior to versions 18.20.1, 20.5.1, and 21.0.1; as well as certified-asterisk prior to 18.9-cert6; Asterisk is susceptible to a DoS due to a race condition in the hello handshake phase of the DTLS protocol when handling DTLS-SRTP for media setup. This attack can be done continuously, thus denying new DTLS-SRTP encrypted calls during the attack. Abuse of this vulnerability may lead to a massive Denial of Service on vulnerable Asterisk servers for calls that rely on DTLS-SRTP. Commit d7d7764cb07c8a1872804321302ef93bf62cba05 contains a fix, which is part of versions 18.20.1, 20.5.1, 21.0.1, amd 18.9-cert6.

MediumCVSS 5.9 · v3.1—No exploit Fix available
Published
Dec 14, 2023
Updated
Jun 17, 2026
EPSS
5.2% · 92th percentile

Report tools

JSON

Action score

25

Monitor

Low priority for now.

CVSS
23 / 40 · 5.9 / 10
CISA KEV
0 / 30 · Not listed
EPSS
2 / 30 · 5.2%

CISA SSVC decision

Exploitation
proof of concept
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
5.9
CNA · GitHub_M
7.5
1.6 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2023-49786

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
digiumasterisk
sangomacertified asterisk

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • digium asteriskbefore 18.20.1
  • digium asterisk19.0.0 and later · before 20.5.1
  • digium asterisk21.0.0
  • sangoma certified asterisk13.13.0
  • sangoma certified asterisk16.8.0
  • sangoma certified asterisk18.9

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • asterisk asterisk

    • < 18.20.1, >= 19.0.0, < 20.5.1, = 21.0.0, < 18.9-cert6affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Alpine:v3.16asteriskfrom 19.0.0 · before 18.20.2-r018.20.2-r0
Alpine:v3.19asteriskfrom 19.0.0 · before 20.5.1-r020.5.1-r0
Debian:10asteriskbefore 1:16.28.0~dfsg-0+deb10u41:16.28.0~dfsg-0+deb10u4
Debian:11asteriskbefore 1:16.28.0~dfsg-0+deb11u41:16.28.0~dfsg-0+deb11u4
Debian:14asteriskbefore 1:20.5.1~dfsg+~cs6.13.40431414-11:20.5.1~dfsg+~cs6.13.40431414-1

Same product

digium: all records

Other highest-scoring records for the same primary product.

  • CVE-2006-5444Integer overflow in the get_input function in the Skinny channel driver (chan_skinny.c) in Asterisk 1.0.x before 1.0.12 and 1.2.x before 1.2
    56Plan
  • CVE-2017-17850An 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.
    53Plan
  • CVE-2019-18610An issue was discovered in manager.c in Sangoma Asterisk through 13.x, 16.x, 17.x and Certified Asterisk 13.21 through 13.21-cert4.
    50Plan

Published before and after this one in the same product

  • ← EarlierCVE-2022-26651Apr 15, 2022 · An issue was discovered in Asterisk through 19.x and Certified Asterisk through 16.8-cert13.
    41Plan
  • ← EarlierCVE-2023-37457Dec 14, 2023 · Asterisk's PJSIP_HEADER dialplan function can overwrite memory/cause crash when using 'update'
    32Monitor
  • ← EarlierCVE-2023-49294Dec 14, 2023 · Asterisk Path Traversal vulnerability
    44Plan

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
alpine:asterisk18.20.2-r0 · Alpine:v3.16Package registry (OSV)
debian:asterisk1:20.5.1~dfsg+~cs6.13.40431414-1 · Debian:14Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-703 · Improper Check or Handling of Exceptional Conditions

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records