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coreutils' comm utility silently corrupts data by performing lossy UTF-8 conversion on all output lines

Low severity GitHub Reviewed Published Apr 22, 2026 to the GitHub Advisory Database • Updated Apr 29, 2026

Package

cargo coreutils (Rust)

Affected versions

< 0.6.0

Patched versions

0.6.0

Description

The comm utility in uutils coreutils silently corrupts data by performing lossy UTF-8 conversion on all output lines. The implementation uses String::from_utf8_lossy(), which replaces invalid UTF-8 byte sequences with the Unicode replacement character (U+FFFD). This behavior differs from GNU comm, which processes raw bytes and preserves the original input. This results in corrupted output when the utility is used to compare binary files or files using non-UTF-8 legacy encodings.

References

Published by the National Vulnerability Database Apr 22, 2026
Published to the GitHub Advisory Database Apr 22, 2026
Last updated Apr 29, 2026
Reviewed Apr 29, 2026

Severity

Low

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

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

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(2nd percentile)

Weaknesses

Improper Handling of Unicode Encoding

The product does not properly handle when an input contains Unicode encoding. Learn more on MITRE.

CVE ID

CVE-2026-35346

GHSA ID

GHSA-hwhf-8p2f-45wr

Source code

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