CVE-2026-53759: Linuxfabrik lib · Linuxfabrik Monitoring Plugins allow insecure creation of SQLite databases
Affects linuxfabrik-libSource GCVE Database
Public exploit available · CVSS 2.0 Low : upgrade to 4.2.0 as a priority.
Data as of 28 Oct 2026, 05:11 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 8% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 4.2.0
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:PExploitation evidence
t = 0 is the CVE’s publication on cve.org
Disclosed: evidence found.
CVE published 18 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: evidence found.
CISA SSVC: proof of concept public
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
Timeline
CVE ID reserved
by GitHub, Inc.
, 69 days before disclosure
CVE published
on cve.org
, t = 0
CISA SSVC assessment
proof of concept public
, 3 days after disclosure
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA SSVC, the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade linuxfabrik-lib to 4.2.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| PyPIlinuxfabrik-lib | Affected
| Fixed in
|
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Description
### Summary The SQLite databases are created at predictable (static) paths in `/tmp`. Any user can therefore create a symlink at these paths in /tmp pointing to arbitrary files. The monitoring scripts then follows these symlinks and then creates their database at the symlink target. This becomes really dangerous for the scripts which can be executed as root with sudo. With this, an attacker can write to abitrary paths. ### PoC The docker-stats check command here as an example. Because writing to /tmp is the default behaviour, the other check commands which use a SQLite database are also very likely affected. ``` # Create the symlink as nagios user nagios@test-server:/tmp$ ln -s /root/nagios-was-here /tmp/linuxfabrik-monitoring-plugins-docker-stats.db # Trigger the execution nagios user nagios@test-server:/tmp$ sudo /usr/lib64/nagios/plugins/docker-stats ``` Check whether or not file was created. ``` root@test-server:/# file /root/nagios-was-here /root/nagios-was-here: SQLite 3.x database, last written using SQLite version 3046001, file counter 2, database pages 3, cookie 0x2, schema 4, UTF-8, version-valid-for 2 ``` ### Impact In it's basic form, this vulnerbility can lead to a denial of service, impacting users who use the provided sudoers file and who didn't take any special precautions like systemd's `PrivateTemp`. It requires that an attacker already compromised the nagios account (which is quite a high barrier to be honest). If any application on the server relies on a SQLite database, there are scenarios where this vulnerability allows for content in existing SQLite databases to be modified. An attacker could let the symlink point to an existing SQLite database and create in /tmp a specially-crafted SQLite Rollback Journal (`.db-journal`) or Write-Ahead-Log (`.db-wal`), which is then applied to the database. ### Fix A proposed fix would be to create a separate directory inside /tmp per user (e.g.,` /tmp/linuxfabrik-monitoring-plugins-{os.geteuid()}`). After creating this directory (or using an already existing one), check the following: ``` # Use os.lstat() instead of os.stat() so we don't accidentally follow symlinks dir_stat = os.lstat(TMP_DIR_PATH) # Ensure the directory is a real dir and not a Symlink if not stat.S_ISDIR(dir_stat.st_mode): # abort the execution sys.exit(1) # Verify the owner if dir_stat.st_uid != os.getuid(): # abort the execution sys.exit(1) # Verify the permissions if (dir_stat.st_mode & 0o077) != 0: # abort the execution sys.exit(1) ```