CVE-2026-35366: printenv Environment Variables With Invalid UTF-8 Vulnerability

MODERATE
Advisory Identifier: GHSA-p7h3-7q52-72w8
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CVSS 4.4
CWE-116 CWE-754
Published
Advisory Summary

CVE-2026-35366 is a MODERATE (CVSS 4.4) environment variables with invalid utf-8 vulnerability (CWE-116: Improper Encoding or Escaping of Output) affecting printenv libraries in the crates.io ecosystem. The issue involves environment variables with invalid utf-8 are silently skipped (evades inspection). Remediation is available by upgrading affected packages to version 0.6.0.

CVE-2026-35366 at a Glance

CVE Identifier CVE-2026-35366
GHSA Identifier GHSA-p7h3-7q52-72w8
Severity MODERATE
CVSS v3.1 Base Score 4.4
CWE Classification CWE-116: Improper Encoding or Escaping of Output
Affected Product printenv
Package Ecosystem crates.io
Published Date
Last Updated

Security Impact

CVSS: 4.4

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N).

Attack Vector Local (AV:L)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality Low (C:L)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2026-35366

To remediate this vulnerability, upgrade all affected printenv dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

uu_printenv fixed: 0.6.0 
Upgrade uu_printenv to 0.6.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for uu_printenv

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-35366, inspect your project dependencies for printenv:

inspect dependencies for uu_printenv

Analyze the terminal output to locate any version of printenv in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.6.0), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-116: Improper Encoding or Escaping of Output, where the product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. as a result, the intended structure of the message is not preserved. In printenv, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

The printenv utility in uutils coreutils fails to display environment variables containing invalid UTF-8 byte sequences. While POSIX permits arbitrary bytes in environment strings, the uutils implementation silently skips these entries rather than printing the raw bytes. This vulnerability allows malicious environment variables (e.g., adversarial LD_PRELOAD values) to evade inspection by administrators or security auditing tools, potentially allowing library injection or other environment-based attacks to go undetected. --- _Zellic finding 3.66. Reported in the Zellic *uutils coreutils Program Security Assessment* (for Canonical, Jan 2026), audited commit `3a07ffc5a9bd4c283e75afa548ba1f1957bad242`._

CVE-2026-35366 Affected printenv Versions

1 component(s)
Fixed Versions:
0.6.0
Product / Package Ecosystem Affected Versions Fixed Version
uu_printenv
 crates.io
< 0.6.0
0.6.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/uutils/coreutils/security/advisories/GHSA-p7h3-7q52-72w8
NVD — CVE-2026-35366 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-35366
printenv Source Repository REPOSITORY
https://github.com/uutils/coreutils/issues/9701
printenv Source Repository REPOSITORY
https://github.com/uutils/coreutils/pull/9728
Security Fix Commit FIX COMMIT
https://github.com/uutils/coreutils/commit/0bfbbc00c7895c0fb6ea94987b4aab99e3d7ee52
printenv Source Repository REPOSITORY
https://github.com/uutils/coreutils
printenv Release RELEASE
https://github.com/uutils/coreutils/releases/tag/0.6.0

Frequently Asked Questions

What is CVE-2026-35366?
CVE-2026-35366 is a security vulnerability in printenv involving environment variables with invalid UTF-8 are silently skipped (evades inspection) under CWE-116: Improper Encoding or Escaping of Output.
Which printenv versions are affected?
Affected versions include releases prior to 0.6.0 across affected packages: uu_printenv.
What version fixes CVE-2026-35366?
Upgrading to 0.6.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is uu_printenv affected?
Yes, uu_printenv is affected in releases prior to 0.6.0. Upgrade your dependency to 0.6.0 or later.
What is the CVSS score of CVE-2026-35366?
CVE-2026-35366 has a CVSS v3.1 base score of 4.4 (MODERATE) with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N.
What CWE is associated with CVE-2026-35366?
CVE-2026-35366 is classified under CWE-116: Improper Encoding or Escaping of Output (The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved.).
How can I check crates.io dependencies for CVE-2026-35366?
Run the dependency tree command: 'inspect dependencies for uu_printenv'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-p7h3-7q52-72w8",
  "modified" : "2026-07-06T20:25:42Z",
  "published" : "2026-07-06T20:25:42Z",
  "aliases" : [ "CVE-2026-35366" ],
  "summary" : "printenv: environment variables with invalid UTF-8 are silently skipped (evades inspection)",
  "details" : "The printenv utility in uutils coreutils fails to display environment variables containing invalid UTF-8 byte sequences. While POSIX permits arbitrary bytes in environment strings, the uutils implementation silently skips these entries rather than printing the raw bytes. This vulnerability allows malicious environment variables (e.g., adversarial LD_PRELOAD values) to evade inspection by administrators or security auditing tools, potentially allowing library injection or other environment-based attacks to go undetected.\n\n---\n_Zellic finding 3.66. Reported in the Zellic *uutils coreutils Program Security Assessment* (for Canonical, Jan 2026), audited commit `3a07ffc5a9bd4c283e75afa548ba1f1957bad242`._",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "uu_printenv"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.6.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/uutils/coreutils/security/advisories/GHSA-p7h3-7q52-72w8"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-35366"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/uutils/coreutils/issues/9701"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/uutils/coreutils/pull/9728"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/uutils/coreutils/commit/0bfbbc00c7895c0fb6ea94987b4aab99e3d7ee52"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/uutils/coreutils"
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    "type" : "WEB",
    "url" : "https://github.com/uutils/coreutils/releases/tag/0.6.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-116", "CWE-754" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-06T20:25:42Z",
    "nvd_published_at" : null
  }
}