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NVD / CVE Program· CNA mitre

CVE-2021-32558: An issue was discovered in Sangoma Asterisk 13.x before 13.38.3, 16.x before 16.19.1, 17.x before 17.9.4, and 18.x before 18.5.1, and…

Noroxi assessment

Priority: Monitor (action score 33/100)

  • 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: 9.2% (FIRST EPSS); higher than 95.3% 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. No special conditions are required; it is repeatable.
  • Fixed version: asterisk (Alpine:v3.11) 16.6.2-r1; asterisk (Alpine:v3.12) 16.16.1-r1; asterisk (Alpine:v3.13) 18.2.1-r2.

Low priority for now. Upgrade to asterisk (Alpine:v3.11) 16.6.2-r1; asterisk (Alpine:v3.12) 16.16.1-r1; asterisk (Alpine:v3.13) 18.2.1-r2 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

An issue was discovered in Sangoma Asterisk 13.x before 13.38.3, 16.x before 16.19.1, 17.x before 17.9.4, and 18.x before 18.5.1, and Certified Asterisk before 16.8-cert10. If the IAX2 channel driver receives a packet that contains an unsupported media format, a crash can occur.

HighCVSS 7.5 · v3.1—No exploit Fix available
Published
Jul 30, 2021
Updated
Jun 16, 2026
EPSS
9.2% · 95th percentile

Report tools

JSON

Action score

33

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
3 / 30 · 9.2%

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-2021-32558

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
digiumcertified asterisk
debiandebian linux

Affected versions

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

  • debian debian linux11.0
  • debian debian linux9.0
  • digium asterisk17.0.0 and later · before 17.9.4
  • digium asterisk13.0.0 and later · before 13.38.3
  • digium asterisk18.0.0 and later · before 18.15.1
  • digium asterisk16.0.0 and later · before 16.19.1
  • digium certified asterisk16.8

Package-level exposure

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

EcosystemPackageAffected rangeFix
Alpine:v3.11asteriskfrom 13.0.0 · before 16.6.2-r116.6.2-r1
Alpine:v3.12asteriskfrom 13.0.0 · before 16.16.1-r116.16.1-r1
Alpine:v3.13asteriskfrom 13.0.0 · before 18.2.1-r218.2.1-r2
Alpine:v3.14asteriskfrom 13.0.0 · before 18.2.2-r218.2.2-r2
Debian:11asteriskbefore 1:16.16.1~dfsg-1+deb11u11:16.16.1~dfsg-1+deb11u1
Debian:14asteriskbefore 1:16.16.1~dfsg-21:16.16.1~dfsg-2
Debian:9asteriskbefore 1:13.14.1~dfsg-2+deb9u51:13.14.1~dfsg-2+deb9u5

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…
    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-2021-26713Feb 19, 2021 · A stack-based buffer overflow in res_rtp_asterisk.c in Sangoma Asterisk before 16.16.1, 17.x before 17.9.2, and 18.x before 18.2.1 and…
    27Monitor
  • ← EarlierCVE-2021-31878Jul 30, 2021 · An issue was discovered in PJSIP in Asterisk before 16.19.1 and before 18.5.1.
    27Monitor
  • Later →CVE-2022-26498Apr 15, 2022 · An issue was discovered in Asterisk through 19.x.
    35Monitor

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:asterisk16.6.2-r1 · Alpine:v3.11Package registry (OSV)
debian:asterisk1:16.16.1~dfsg-2 · 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.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

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

No commit or PR link among the references.

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.
  • No special conditions are required; it is repeatable.

If successful

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

Weakness class (CWE)

CWE-74 · Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

CVSS vector

CVSS:3.1/AV:N/AC:L/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.

Change log

  1. Fix✗ → ✓

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

References

Show all references (3 more)

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

All records