CVE-2018-20743: murmur in Mumble through 1.2.19 before 2018-08-31 mishandles multiple concurrent requests that are persisted i

Q: How do I fix CVE-2018-20743?

mumble: upgrade to newer than 1.2.19; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2018-20743 being exploited?

CVE-2018-20743 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-2018-20743 affect?

CVE-2018-20743 affects mumble, debian linux. Severity is high (CVSS 7.5). murmur in Mumble through 1.2.19 before 2018-08-31 mishandles multiple concurrent requests that are persisted in the database, which allows remote attackers to cause a denial of service (daemon hang or crash) via a message flood.

Q: How urgent is CVE-2018-20743?

Priority 59/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

This month

HIGH 7.5REMOTEWATCHLISTUPGRADEMITIGATE

CVE-2018-20743 is a high-severity flaw (CVSS 7.5) affecting mumble, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

murmur in Mumble through 1.2.19 before 2018-08-31 mishandles multiple concurrent requests that are persisted in the database, which allows remote attackers to cause a denial of service (daemon hang or crash) via a message flood.

Why this priority

High severity
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	3.6% (top 10%)
CISA exploited list	No
Weakness	CWE-20
Published	2019-01-25
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: debian · mumble

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

Am I affected?

Timeline

2019-01-25 16:29 UTCPublished CVE record published
2026-06-17 01:53 UTCUpdated Record last modified

mumble mumble UPGRADE

Affected: <= 1.2.19

Fixed in: newer than 1.2.19

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 1.2.19 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade mumble

Note

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

debian debian linux MITIGATE

Affected: 8.0 · 9.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

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-2018-20743?

mumble: upgrade to newer than 1.2.19; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2018-20743 being exploited?

CVE-2018-20743 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-2018-20743 affect?

CVE-2018-20743 affects mumble, debian linux. Severity is high (CVSS 7.5). murmur in Mumble through 1.2.19 before 2018-08-31 mishandles multiple concurrent requests that are persisted in the database, which allows remote attackers to cause a denial of service (daemon hang or crash) via a message flood.

How urgent is CVE-2018-20743?

Priority 59/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Debian vulnerabilities

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References

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