CVE-2026-23738: Asterisk is an open source private branch exchange and telephony toolkit

Q: How do I fix CVE-2026-23738?

asterisk: upgrade to 23.2.2; certified asterisk: upgrade to newer than 18.9. Exact commands for each OS are on this page.

Q: Is CVE-2026-23738 being exploited?

CVE-2026-23738 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-23738 affect?

CVE-2026-23738 affects asterisk, certified asterisk. Severity is low (CVSS 3.5). 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, user supplied/control values for Cookies and any GET variable query Parameter are directly interpo

Q: How urgent is CVE-2026-23738?

Priority 14/100. No elevated risk signals yet.

Routine

LOW 3.5UPGRADEUPGRADE

CVE-2026-23738 is a low-severity flaw (CVSS 3.5) affecting asterisk, certified 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, user supplied/control values for Cookies and any GET variable query Parameter are directly interpolated into the HTML of the page using ast_str_append. The endpoint at GET /httpstatus is the potential vulnerable endpoint relating to asterisk/main /http.c. This issue has been patched in versions 20.7-cert9,

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	3.5 (Low)
Attack vector	Adjacent network
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.2% (top 92%)
CISA exploited list	No
Weakness	CWE-79
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 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: 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 23.2.2 (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.

sangoma certified asterisk UPGRADE

Affected: <= 18.9 · 20.7 cert1 · 20.7 cert1-rc1 · 20.7 cert1-rc2 · 20.7 cert2 · 20.7 cert3 · 20.7 cert4 · 20.7 cert5

Fixed in: newer than 18.9

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 18.9 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade certified-asterisk

Note

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

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-2026-23738?

asterisk: upgrade to 23.2.2; certified asterisk: upgrade to newer than 18.9. Exact commands for each OS are on this page.

Is CVE-2026-23738 being exploited?

CVE-2026-23738 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-2026-23738 affect?

CVE-2026-23738 affects asterisk, certified asterisk. Severity is low (CVSS 3.5). 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, user supplied/control values for Cookies and any GET variable query Parameter are directly interpo

How urgent is CVE-2026-23738?

Priority 14/100. 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-2026-23740 NONE 0.0 DOWNGRADE 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-2025-57767 HIGH 7.5 UPGRADE Asterisk is an open source private branch exchange and telephony toolkit

References

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