CVE-2023-31465: An issue was discovered in FSMLabs TimeKeeper 8.0.17 through 8.0.28

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CRITICAL 9.8REMOTEUPGRADE

CVE-2023-31465 is a critical-severity flaw (CVSS 9.8) affecting timekeeper. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in FSMLabs TimeKeeper 8.0.17 through 8.0.28. By intercepting requests from various timekeeper streams, it is possible to find the getsamplebacklog call. Some query parameters are passed directly in the URL and named arg[x], with x an integer starting from 1; it is possible to modify arg[2] to insert Bash code that will be executed directly by the server.

Why this priority

Critical severity
EPSS top 1%: very likely to be exploited
Public exploit reference
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	46.3% (top 1%)
CISA exploited list	No
Published	2023-07-26
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: fsmlabs

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

Am I affected?

Timeline

2023-07-26 20:15 UTCPublished CVE record published
2026-06-17 05:57 UTCUpdated Record last modified

fsmlabs timekeeper UPGRADE

Affected: >= 8.0.17 and <= 8.0.28

Fixed in: newer than 8.0.28

Safe to downgrade to: a release before 8.0.17

1. Check installed version

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

2. UPGRADE to newer than 8.0.28 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade timekeeper

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 8.0.17 (Debian / Ubuntu)

apt-cache madison timekeeper sudo apt install timekeeper=<VERSION_BEFORE_8.0.17> sudo apt-mark hold timekeeper

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

dnf --showduplicates list timekeeper sudo dnf downgrade timekeeper-<VERSION_BEFORE_8.0.17> sudo dnf versionlock add timekeeper

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.

Exact fixes by distribution

Fedora 46 · borgmatic · FIXED · 2.2.0-1.fc46 · FEDORA-2026-041229e71b · source

sudo dnf upgrade --advisory=FEDORA-2026-041229e71b

Fedora ELN · pie · FIXED · 1.5.4-1.eln159 · FEDORA-2026-a2c0261d3a · source

sudo dnf upgrade --advisory=FEDORA-2026-a2c0261d3a

Public exploits and detection

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

Write-up: github.com/CapgeminiCisRedTeam/Disclosure/blob/main/CVE%20PoC/CVE-2023-31465.md
Nuclei scan template: TimeKeeper by FSMLabs - Remote Code Execution

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-2023-31465?

timekeeper: upgrade to newer than 8.0.28. Exact commands for each OS are on this page.

Is CVE-2023-31465 being exploited?

CVE-2023-31465 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-2023-31465 affect?

CVE-2023-31465 affects timekeeper. Severity is critical (CVSS 9.8). An issue was discovered in FSMLabs TimeKeeper 8.0.17 through 8.0.28. By intercepting requests from various timekeeper streams, it is possible to find the getsamplebacklog call. Some query parameters are passed directly in the URL and named

How urgent is CVE-2023-31465?

Priority 72/100. Critical severity; EPSS top 1%: very likely to be exploited; Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action

Related CVEs

CVE-2023-31466 MEDIUM 5.4 UPGRADE An XSS issue was discovered in FSMLabs TimeKeeper 8.0.17

References

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