CVE Intelligence
Medium Logic error exploit reference

CVE-2026-35366 — uutils coreutils printenv Security Inspection Bypass via UTF-8 Enforcement

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.

Published Apr 22, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: canonical

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.2% (30-day exploitation probability)+1
  • Technical severity (medium)+3
  • CISA SSVC: exploitation "poc"+5

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.19%
ahead of 8% of scored CVEs · Oct 14, 2026
Affects
Uutils
Coreutils
CVSS base
4.4
Medium · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
Proof of concept
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

  • Documented patch — github.com (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Uutils Coreutils).
  2. Apply the fixed version or the patch documented under Remediation.
  3. Search available logs for exploit probes matching the vulnerability class (logic error), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Uutils Coreutils < 0.6.0 Vulnerable NIST National Vulnerability Database
Uutils Coreutils < 0.6.0 Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
4.4 CVSS 3.1 Medium 1.8 2.5 security@ubuntu.com via NIST National Vulnerability Database
4.4 CVSS 3.1 Medium — — canonical via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N (score shown at the top: security@ubuntu.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-754 · Improper Check for Unusual or Exceptional Conditions

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.19%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
endpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · uutils/coreutils
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • Fix documented
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVSS changed · 4.4
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Analyzed
    Oct 13, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVE published
    Apr 22, 2026 · canonical

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

3 on the record

Elsewhere on this site

Uutils
every CVE for this vendor
Logic error
same class
CWE-754
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-35381 uutils coreutils cut Local Logic Error and Data Integrity Issue in Output Filtering Apr 22, 2026
  • CVE-2026-35380 uutils coreutils cut Local Logic Error and Data Integrity Issue in Delimiter Parsing Apr 22, 2026
  • CVE-2026-35376 uutils coreutils chcon Security Bypass and Mandatory Access Control (MAC) Inconsistency via TOCTOU Race Condition Apr 22, 2026
  • CVE-2026-35374 uutils coreutils split Arbitrary File Truncation via Time-of-Check to Time-of-Use (TOCTOU) Race Condition Apr 22, 2026
  • CVE-2026-35375 uutils coreutils split Local Data Integrity Issue via Lossy Filename Encoding Apr 22, 2026
  • CVE-2026-35377 uutils coreutils env Local Denial of Service via Improper Handling of Backslashes in Split-String Mode Apr 22, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-35366 is "uutils coreutils printenv Security Inspection Bypass via UTF-8 Enforcement", rated Medium. It affects Coreutils (Uutils); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 4.4 describes technical severity. EPSS 0.19% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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