slopsmith: Improper Limitation of a Pathname to a Restricted Directory
CVE-2026-49290 is a high-severity improper limitation of a pathname to a restricted directory vulnerability in slopsmith from Byrongamatos, with a CVSS 4.0 base score of 7.6 out of 10. It can be exploited remotely over the network by an attacker with administrator privileges, without any action from a user. Affected slopsmith versions: < 0.2.9-alpha.5. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.83% chance of exploitation within 30 days, higher than 58% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of slopsmith 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.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Byrongamatos | slopsmith | < 0.2.9-alpha.5 | 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
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Attack requirements
- NoneThe attack does not depend on a particular deployment or configuration.
- Privileges required
- HighAdministrator-level access is required first.
- User interaction
- NoneNo action by a victim is required.
- Confidentiality (vulnerable system)
- HighSerious loss of confidentiality on the vulnerable system.
- Integrity (vulnerable system)
- HighSerious loss of integrity on the vulnerable system.
- Availability (vulnerable system)
- HighSerious loss of availability on the vulnerable system.
- Confidentiality (other systems)
- HighSerious loss of confidentiality on systems beyond the vulnerable one.
- Integrity (other systems)
- HighSerious loss of integrity on systems beyond the vulnerable one.
- Availability (other systems)
- HighSerious loss of availability on systems beyond the vulnerable one.
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. Scored by CNA (github.com).
Official description
Slopsmith is a self-contained web application for browsing, playing, and practicing Rocksmith 2014 Custom DLC (CDLC). Prior to 0.2.9-alpha.5, a path-traversal vulnerability in Slopsmith's archive extractors allows an attacker to write arbitrary files outside the extraction directory by supplying a crafted PSARC or sloppak archive. With the default Docker configuration (running as root) and the ability to drop a file into the plugin directory, this escalates to arbitrary remote code execution on the host. Three archive extractors concatenated archive-entry filenames directly onto the extraction root without validation: `lib/psarc.py::unpack_psarc` — PSARC TOC filenames; `lib/patcher.py::unpack_psarc` — duplicate of the above in the patcher flow; `lib/sloppak.py::_unpack_zip` — bare `ZipFile.extractall()` with no member filter. Each accepts entry names containing `..` segments, absolute paths, or backslash separators. The Python `zipfile` module's default `extractall()` is documented as not preventing traversal when callers don't supply a member-filter callback. Version 0.2.9-alpha.5 patches the issue. Until updated, do not open PSARC or sloppak archives from untrusted sources, and do not expose the Slopsmith instance to the public internet. Docker users should also pull the latest image after the next slopsmith Docker image is published.
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: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Improper Limitation of a Pathname to a Restricted Directory vulnerabilities
- 8.1 High severity
- 7.1 High severity
- 9.1 Critical severity
- 9.8 Critical severity
- 8.8 High severity
- 7.7 High severity
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