CVE-2021-45848: Denial of service (DoS) vulnerability in Nicotine+ 3.0.3 and later allows a user with a modified Soulseek clie

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HIGH 7.5REMOTEUPGRADEMITIGATE

CVE-2021-45848 is a high-severity flaw (CVSS 7.5) affecting nicotine\+, fedora. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Denial of service (DoS) vulnerability in Nicotine+ 3.0.3 and later allows a user with a modified Soulseek client to crash Nicotine+ by sending a file download request with a file path containing a null character.

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

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	1.6% (top 24%)
CISA exploited list	No
Weakness	CWE-116
Published	2022-03-15
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: fedoraproject · nicotine-plus

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

Am I affected?

Timeline

2022-03-15 19:15 UTCPublished CVE record published
2026-06-17 04:14 UTCUpdated Record last modified

nicotine-plus nicotine\+ UPGRADE

Affected: >= 3.0.3 and < 3.2.1

Fixed in: 3.2.1

Safe to downgrade to: a release before 3.0.3

1. Check installed version

apt-cache policy nicotine+ || rpm -q nicotine+ || nicotine+ --version

2. UPGRADE to 3.2.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade nicotine+

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade nicotine+

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 3.0.3 (Debian / Ubuntu)

apt-cache madison nicotine+ sudo apt install nicotine+=<VERSION_BEFORE_3.0.3> sudo apt-mark hold nicotine+

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

dnf --showduplicates list nicotine+ sudo dnf downgrade nicotine+-<VERSION_BEFORE_3.0.3> sudo dnf versionlock add nicotine+

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.

fedoraproject fedora MITIGATE

Affected: 34

Fixed in: no fixed release known

Safe to downgrade to: a release before 34

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-2021-45848?

nicotine\+: upgrade to 3.2.1; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-45848 being exploited?

CVE-2021-45848 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-2021-45848 affect?

CVE-2021-45848 affects nicotine\+, fedora. Severity is high (CVSS 7.5). Denial of service (DoS) vulnerability in Nicotine+ 3.0.3 and later allows a user with a modified Soulseek client to crash Nicotine+ by sending a file download request with a file path containing a null character.

How urgent is CVE-2021-45848?

Priority 55/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

References

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