CVE-2026-48687: FastNetMon Community Edition through 1.2.9 contains an OS command injection vulnerability in the Juniper route

Q: How do I fix CVE-2026-48687?

fastnetmon: upgrade to newer than 1.2.9. Exact commands for each OS are on this page.

Q: Is CVE-2026-48687 being exploited?

CVE-2026-48687 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-2026-48687 affect?

CVE-2026-48687 affects fastnetmon. Severity is critical (CVSS 9.8). FastNetMon Community Edition through 1.2.9 contains an OS command injection vulnerability in the Juniper router integration plugin. The _log() function in src/juniper_plugin/fastnetmon_juniper.php (lines 117-118) constructs shell commands b

Q: How urgent is CVE-2026-48687?

Priority 63/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

CRITICAL 9.8REMOTEUPGRADE

CVE-2026-48687 is a critical-severity flaw (CVSS 9.8) affecting fastnetmon. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

FastNetMon Community Edition through 1.2.9 contains an OS command injection vulnerability in the Juniper router integration plugin. The _log() function in src/juniper_plugin/fastnetmon_juniper.php (lines 117-118) constructs shell commands by concatenating the $msg parameter directly into exec() calls: exec("echo `date` \"- {FASTNETMON] - " . $msg . " \" >> " . $FILE_LOG_TMP). The $msg variable contains unsanitized data derived from command-line a

Why this priority

Critical severity
Public exploit reference
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	1.6% (top 24%)
CISA exploited list	No
Weakness	CWE-78
Published	2026-05-26
Last modified	2026-07-21

Publisher (CNA): MITRE · Vendor: pavel-odintsov

Last updated 2026-07-21 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-26 16:16 UTCPublished CVE record published
2026-07-21 19:10 UTCUpdated Record last modified

pavel-odintsov fastnetmon UPGRADE

Affected: <= 1.2.9

Fixed in: newer than 1.2.9

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 1.2.9 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade fastnetmon

Note

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

Exact fixes by distribution

Fedora ELN · clash-meta · FIXED · 1.19.33-1.eln159 · FEDORA-2026-7dfb64c5e1 · source

sudo dnf upgrade --advisory=FEDORA-2026-7dfb64c5e1

Fedora 46 · vulkan-utility-libraries · FIXED · 1.4.363.0-1.fc46 · FEDORA-2026-994176daf5 · source

sudo dnf upgrade --advisory=FEDORA-2026-994176daf5

Debian 12 · fastnetmon · NO FIX YET

Debian 13 · fastnetmon · FIXED · 1.2.9-0+deb13u1

sudo apt update && sudo apt install --only-upgrade fastnetmon dpkg --compare-versions "$(dpkg-query -W -f='${Version}' fastnetmon)" ge "1.2.9-0+deb13u1" && echo PATCHED || echo STILL-VULNERABLE

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-2026-48687?

fastnetmon: upgrade to newer than 1.2.9. Exact commands for each OS are on this page.

Is CVE-2026-48687 being exploited?

CVE-2026-48687 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-2026-48687 affect?

CVE-2026-48687 affects fastnetmon. Severity is critical (CVSS 9.8). FastNetMon Community Edition through 1.2.9 contains an OS command injection vulnerability in the Juniper router integration plugin. The _log() function in src/juniper_plugin/fastnetmon_juniper.php (lines 117-118) constructs shell commands b

How urgent is CVE-2026-48687?

Priority 63/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

PHP vulnerabilities · Juniper Junos vulnerabilities

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References

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