Cribl Stream: UNIX Symbolic Link (Symlink) Following
CVE-2026-56748 is a high-severity UNIX symbolic link (symlink) following vulnerability in Cribl Stream from Cribl, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists version 4.18.2 as the first without the flaw, so updating Cribl Stream to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.92% chance of exploitation within 30 days, higher than 61% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Cribl Stream to 4.18.2 or a later version.
- Read the advisory on trust.cribl.io for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Cribl | Cribl Stream | before 4.18.2 | 4.18.2 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.7 | High | CNA |
| CVSS 3.1 | 8.8 | High | CNA |
Official description
Improper validation of symbolic links in the Pack Git import feature in Cribl Stream before 4.18.2 allows a remote authenticated attacker with Pack import and pipeline preview permissions to execute arbitrary code as the Cribl server process via a crafted Git repository containing a symbolic link in the pack's functions directory.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: UNIX Symbolic Link (Symlink) Following
The product, when opening a file or directory, does not sufficiently account for when the file is a symbolic link that resolves to a target outside of the intended control sphere. This could allow an attacker to cause the product to operate on unauthorized files.
How developers prevent this class of flaw
- Symbolic link attacks often occur when a program creates a tmp directory that stores files/links. Access to the directory should be restricted to the program as to prevent attackers from manipulating the files.
- Follow the principle of least privilege when assigning access rights to entities in a software system. Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.
More UNIX Symbolic Link (Symlink) Following vulnerabilities (CWE-61)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Patches and release notes
Other vulnerabilities in Cribl Stream
- 8.8 High severity
- 8.7 High severity
Recent UNIX Symbolic Link (Symlink) Following vulnerabilities
- 7.3 High severity
- 7.1 High severity
- 7.8 High severity
- 7.3 High severity
- 9.6 Critical severity
- 7.8 High severity
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