CVE-2021-34805: An issue was discovered in FAUST iServer before 9.0.019.019.7

This week

HIGH 7.5REMOTEUPGRADE

CVE-2021-34805 is a high-severity flaw (CVSS 7.5) affecting faust iserver. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in FAUST iServer before 9.0.019.019.7. For each URL request, it accesses the corresponding .fau file on the operating system without preventing %2e%2e%5c directory traversal.

Why this priority

High severity
EPSS top 2%: very likely to be exploited
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	26.8% (top 2%)
CISA exploited list	No
Weakness	CWE-22
Published	2022-01-31
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: land-software

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

Am I affected?

Timeline

2022-01-31 08:15 UTCPublished CVE record published
2026-06-17 03:56 UTCUpdated Record last modified

land-software faust iserver UPGRADE

Affected: >= 9.0.017.017.1-3 and < 9.0.019.019.7

Fixed in: 9.0.019.019.7

Safe to downgrade to: a release before 9.0.017.017.1-3

1. Check installed version

apt-cache policy faust-iserver || rpm -q faust-iserver || faust-iserver --version

2. UPGRADE to 9.0.019.019.7 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade faust-iserver

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade faust-iserver

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 9.0.017.017.1-3 (Debian / Ubuntu)

apt-cache madison faust-iserver sudo apt install faust-iserver=<VERSION_BEFORE_9.0.017.017.1-3> sudo apt-mark hold faust-iserver

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

dnf --showduplicates list faust-iserver sudo dnf downgrade faust-iserver-<VERSION_BEFORE_9.0.017.017.1-3> sudo dnf versionlock add faust-iserver

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.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Nuclei scan template: FAUST iServer 9.0.018.018.4 - Local File Inclusion

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-2021-34805?

faust iserver: upgrade to 9.0.019.019.7. Exact commands for each OS are on this page.

Is CVE-2021-34805 being exploited?

CVE-2021-34805 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-2021-34805 affect?

CVE-2021-34805 affects faust iserver. Severity is high (CVSS 7.5). An issue was discovered in FAUST iServer before 9.0.019.019.7. For each URL request, it accesses the corresponding .fau file on the operating system without preventing %2e%2e%5c directory traversal.

How urgent is CVE-2021-34805?

Priority 61/100. High severity; EPSS top 2%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action

References

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