joker: Inclusion of Functionality from Untrusted Control Sphere
CVE-2026-59172 is a high-severity inclusion of functionality from untrusted control sphere vulnerability in joker from Candid82, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. Affected joker versions: < 1.8.2. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.16% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of joker you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
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
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- 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:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by CNA (github.com).
Official description
Joker is a small Clojure interpreter, linter and formatter written in Go. Prior to 1.8.2, `joker --lint <file>` walks upward from the linted file to locate a `.jokerd/` directory and executes matching `linter.*` files before linting. Those files contain executable Joker/Clojure code, so linting a file inside an untrusted repository can execute repository-supplied code with the linter user's privileges. Editor integrations and CI jobs that automatically lint checked-out source can trigger this behavior. The patch stops executing project-local linter customizations and loads executable customization only from the user's home directory. This issue is fixed in version 1.8.2.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Inclusion of Functionality from Untrusted Control Sphere
The product imports, requires, or includes executable functionality (such as a library) from a source that is outside of the intended control sphere.
How developers prevent this class of flaw
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs. For example, ID 1 could map to inbox.txt and ID 2 could map to profile.txt. Features such as the ESAPI AccessReferenceMap provide this capability.
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
More Inclusion of Functionality from Untrusted Control Sphere vulnerabilities (CWE-829)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
References
Patches and release notes
Other references
Recent Inclusion of Functionality from Untrusted Control Sphere vulnerabilities
- 8.1 High severity
- 7.8 High severity
- 8.4 High severity
- 8.8 High severity
- 8.3 High severity
- 9.9 Critical severity
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