CVE-2026-23740: Asterisk is an open source private branch exchange and telephony toolkit

Routine

NONE 0.0DOWNGRADEUPGRADE

CVE-2026-23740 is a none-severity flaw (CVSS 0.0) affecting certified asterisk, asterisk. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Asterisk is an open source private branch exchange and telephony toolkit. Prior to versions 20.7-cert9, 20.18.2, 21.12.1, 22.8.2, and 23.2.2, when ast_coredumper writes its gdb init and output files to a directory that is world-writable (for example /tmp), an attacker with write permission(which is all users on a linux system) to that directory can cause root to execute arbitrary commands or overwrite arbitrary files by controlling the gdb init f

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	0.0 (None)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.1% (top 97%)
CISA exploited list	No
Weakness	CWE-427
Published	2026-02-06
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: sangoma

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-02-06 17:16 UTCPublished CVE record published
2026-06-17 10:22 UTCUpdated Record last modified

sangoma certified asterisk DOWNGRADE

Affected: 13.13.0 · 13.13.0 cert1 · 13.13.0 cert1-rc1 · 13.13.0 cert1-rc2 · 13.13.0 cert1-rc3 · 13.13.0 cert1-rc4 · 13.13.0 cert2 · 13.13.0 cert3

Fixed in: no fixed release known

Safe to downgrade to: a release before 13.13.0

1. Check installed version

apt-cache policy certified-asterisk || rpm -q certified-asterisk || certified-asterisk --version

2. No fixed release: DOWNGRADE to a release before 13.13.0 (Debian / Ubuntu)

apt-cache madison certified-asterisk sudo apt install certified-asterisk=<VERSION_BEFORE_13.13.0> sudo apt-mark hold certified-asterisk

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list certified-asterisk sudo dnf downgrade certified-asterisk-<VERSION_BEFORE_13.13.0> sudo dnf versionlock add certified-asterisk

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

sangoma asterisk UPGRADE

Affected: < 20.18.2 · >= 21.0.0 and < 21.12.1 · >= 22.0.0 and < 22.8.2 · >= 23.0.0 and < 23.2.2

Fixed in: 20.18.2, 21.12.1, 22.8.2, 23.2.2

Safe to downgrade to: a release before 21.0.0

1. Check installed version

apt-cache policy asterisk || rpm -q asterisk || asterisk --version

2. UPGRADE to 20.18.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade asterisk

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade asterisk

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 21.0.0 (Debian / Ubuntu)

apt-cache madison asterisk sudo apt install asterisk=<VERSION_BEFORE_21.0.0> sudo apt-mark hold asterisk

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list asterisk sudo dnf downgrade asterisk-<VERSION_BEFORE_21.0.0> sudo dnf versionlock add asterisk

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-23740?

certified asterisk: downgrade or apply the listed mitigation; asterisk: upgrade to 20.18.2, 21.12.1, 22.8.2, 23.2.2. Exact commands for each OS are on this page.

Is CVE-2026-23740 being exploited?

CVE-2026-23740 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-23740 affect?

CVE-2026-23740 affects certified asterisk, asterisk. Severity is none (CVSS 0.0). Asterisk is an open source private branch exchange and telephony toolkit. Prior to versions 20.7-cert9, 20.18.2, 21.12.1, 22.8.2, and 23.2.2, when ast_coredumper writes its gdb init and output files to a directory that is world-writable (fo

How urgent is CVE-2026-23740?

Priority 1/100. No elevated risk signals yet.

Related CVEs

CVE-2025-1131 HIGH 7.8 UPGRADE DOWNGRADE A local privilege escalation vulnerability exists in the safe_asterisk script included with the Asterisk toolk
CVE-2026-23741 NONE 0.0 UPGRADE UPGRADE Asterisk is an open source private branch exchange and telephony toolkit
CVE-2026-23739 LOW 2.0 UPGRADE UPGRADE Asterisk is an open source private branch exchange and telephony toolkit
CVE-2026-23738 LOW 3.5 UPGRADE UPGRADE Asterisk is an open source private branch exchange and telephony toolkit
CVE-2025-54995 MEDIUM 6.5 UPGRADE UPGRADE Asterisk is an open source private branch exchange and telephony toolkit

References

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