pymanager: Uncontrolled Search Path Element
CVE-2026-5271 is a high-severity uncontrolled search path element vulnerability in pymanager from Python Software Foundation, 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 version 26.1 as the first without the flaw, so updating pymanager to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.18% 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 pymanager to 26.1 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 |
|---|---|---|---|
| Python Software Foundation | pymanager | 26.0 up to, but not including, 26.1 | 26.1 |
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 | 5.6 | Medium | CNA (python.org) |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
pymanager included the current working directory in sys.path meaning modules could be shadowed by modules in the current working directory. As a result, if a user executes a pymanager-generated command (e.g., pip, pytest) from an attacker-controlled directory, a malicious module in that directory can be imported and executed instead of the intended package.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Uncontrolled Search Path Element
The product uses a fixed or controlled search path to find resources, but one or more locations in that path can be under the control of unintended actors.
How developers prevent this class of flaw
- Hard-code the search path to a set of known-safe values (such as system directories), or only allow them to be specified by the administrator in a configuration file. Do not allow these settings to be modified by an external party. Be careful to avoid related weaknesses such as CWE-426 and CWE-428.
- When invoking other programs, specify those programs using fully-qualified pathnames. While this is an effective approach, code that uses fully-qualified pathnames might not be portable to other systems that do not use the same pathnames. The portability can be improved by locating the full-qualified paths in a centralized, easily-modifiable location within the source code, and having the code refer to these paths.
- Remove or restrict all environment settings before invoking other programs. This includes the PATH environment variable, LD_LIBRARY_PATH, and other settings that identify the location of code libraries, and any application-specific search paths.
More Uncontrolled Search Path Element vulnerabilities (CWE-427)
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
Third-party and government advisories
- openwall.com/lists/oss-security/2026/04/01/5Mailing List, Third Party Advisory
Recent Uncontrolled Search Path Element vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 8.4 High severity
- 8.4 High severity
- 8.8 High severity
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