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CVE-2026-57197NVD status: Awaiting Analysis

asterisk: Heap-based Buffer Overflow

Published Updated By the CyberSecBulletin desk

CVE-2026-57197 is a high-severity heap-based buffer overflow vulnerability in asterisk, with a CVSS 4.0 base score of 7.7 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected asterisk versions: < 20.20.1; >= 21.0.0-pre1, < 21.12.3; >= 22.0.0-pre1, < 22.10.1, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.53% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of asterisk you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on github.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
Asteriskasterisk< 20.20.1; >= 21.0.0-pre1, < 21.12.3; >= 22.0.0-pre1, < 22.10.1; >= 23.0.0-pre1, < 23.4.1Not stated
Asteriskcertified-asterisk< 20.7-cert11; >= 22.8-cert1-pre1, < 22.8-cert3Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Attack requirements
PresentThe target must be in a specific state or configuration for the attack to work.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Confidentiality (vulnerable system)
HighSerious loss of confidentiality on the vulnerable system.
Integrity (vulnerable system)
HighSerious loss of integrity on the vulnerable system.
Availability (vulnerable system)
HighSerious loss of availability on the vulnerable system.
Confidentiality (other systems)
NoneNo loss of confidentiality on systems beyond the vulnerable one.
Integrity (other systems)
NoneNo loss of integrity on systems beyond the vulnerable one.
Availability (other systems)
NoneNo loss of availability on systems beyond the vulnerable one.

Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. Scored by CNA (github.com).

Official description

Asterisk is an open source private branch exchange and telephony toolkit. 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 unbounded `memcpy` of `OGG/Speex` packet data in `format_ogg_speex` can cause a heap buffer overflow and crash Asterisk when reading a file containing corrupted Speex audio. The attacker must create the file and make it available to Asterisk either through sufficiently elevated privileges or by convincing an Asterisk administrator to make it available. Asterisk must also be configured to play that file. This issue is fixed in Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 20.7-cert11, 22.8-cert3.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Heap-based Buffer Overflow

The product writes past the end of a buffer that was allocated on the heap.

How developers prevent this class of flaw

  • Pre-design: Use a language or compiler that performs automatic bounds checking.
  • Use an abstraction library to abstract away risky APIs. Not a complete solution.
  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.

More Heap-based Buffer Overflow vulnerabilities (CWE-122)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Patches and release notes

Other vulnerabilities in asterisk

All asterisk vulnerabilities

Recent Heap-based Buffer Overflow vulnerabilities

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