Gleam: Improper Limitation of a Pathname to a Restricted Directory
CVE-2026-32146 is a high-severity improper limitation of a pathname to a restricted directory vulnerability in Gleam, 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. The record lists versions 1.15.4, 1.16.0-rc2, v1.15.4-elixir as the first without the flaw, so updating Gleam to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.26% 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
- Update Gleam to 1.15.4 or 1.16.0-rc2 or v1.15.4-elixir or v1.15.4-erlang, whichever matches your release line, or a later version.
- 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
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Gleam | Gleam | 1.9.0-rc1 up to, but not including, 1.15.4; 1.16.0-rc1 up to, but not including, 1.16.0-rc2; v1.9.0-rc1-elixir up to, but not including, v1.15.4-elixir; v1.9.0-rc1-erlang up to, but not including, v1.15.4-erlang; v1.9.0-rc1-node up to, but not including, v1.15.4-node; v1.9.0-rc1-node-slim up to, but not including, v1.15.4-node-slim; v1.9.0-rc1-elixir-slim up to, but not including, v1.15.4-elixir-slim; v1.9.0-rc1-erlang-slim up to, but not including, v1.15.4-erlang-slim; and 15 more ranges | 1.15.4, 1.16.0-rc2, v1.15.4-elixir, v1.15.4-erlang, v1.15.4-node, v1.15.4-node-slim |
| Red Hat | Red Hat Enterprise Linux 10 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 7 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9 | Not specified in the record | Not stated |
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 NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.3 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
| CVSS 3.1 | 8.6 | High | CNA |
Official description
Improper path validation vulnerability in the Gleam compiler's handling of git dependencies allows arbitrary file system modification during dependency download. Dependency names from gleam.toml and manifest.toml are incorporated into filesystem paths without sufficient validation or confinement to the intended dependency directory, allowing attacker-controlled paths (via relative traversal such as ../ or absolute paths) to target filesystem locations outside that directory. When resolving git dependencies (e.g. via gleam deps download), the computed path is used for filesystem operations including directory deletion and creation. This vulnerability occurs during the dependency resolution and download phase, which is generally expected to be limited to fetching and preparing dependencies within a confined directory. A malicious direct or transitive git dependency can exploit this issue to delete and overwrite arbitrary directories outside the intended dependency directory, including attacker-chosen absolute paths, potentially causing data loss. In some environments, this may be further leveraged to achieve code execution, for example by overwriting git hooks or shell configuration files. This issue affects gleam: from 1.9.0-rc1 before 1.15.4 and from 1.16.0-rc1 before 1.16.0-rc2.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Limitation of a Pathname to a Restricted Directory
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
How developers prevent this class of flaw
- 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.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.
More Improper Limitation of a Pathname to a Restricted Directory vulnerabilities (CWE-22)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Patches and release notes
- github.com/gleam-lang/gleam/commit/1aa5d8e594b0aa240bb213fce6ee19c65e6d5bcf
- github.com/gleam-lang/gleam/commit/2dc0467f822c75de94697a912755d172928ee40a
- github.com/gleam-lang/gleam/commit/92aae3913570e8d8962f6399404777d313045bfa
- github.com/gleam-lang/gleam/commit/a4fde22445ab8e5cc79c2ff48971616cb570702c
Third-party and government advisories
- cna.erlef.org/cves/CVE-2026-32146.htmlThird Party Advisory
- osv.dev/vulnerability/EEF-CVE-2026-32146Third Party Advisory
Other references
Other vulnerabilities in Gleam
- 7.6 High severity
Recent Improper Limitation of a Pathname to a Restricted Directory vulnerabilities
- 7.5 High severity
- 8.2 High severity
- 8.3 High severity
- 8.8 High severity
- 7.7 High severity
- 9.8 Critical severity
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