CVE-2026-35346: CWE-176: Improper Handling of Unicode Encoding in Uutils coreutils
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.
AI Analysis
Technical Summary
The comm utility in uutils coreutils improperly handles Unicode encoding by converting all output lines using String::from_utf8_lossy(), causing invalid UTF-8 sequences to be replaced with the Unicode replacement character. This results in silent data corruption when processing binary or non-UTF-8 encoded files, diverging from GNU comm's behavior that preserves raw input bytes. The issue is classified under CWE-176 (Improper Handling of Unicode Encoding) and has a CVSS 3.3 (low) score, reflecting limited impact confined to data integrity.
Potential Impact
The vulnerability causes silent corruption of output data by replacing invalid UTF-8 byte sequences with a replacement character, which affects the integrity of output when comm is used on binary or legacy-encoded files. There is no impact on confidentiality or availability. No known exploits are reported in the wild.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, users should avoid using uutils coreutils comm for comparing binary or non-UTF-8 encoded files or use alternative tools such as GNU comm that preserve raw byte data.
CVE-2026-35346: CWE-176: Improper Handling of Unicode Encoding in Uutils coreutils
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.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The comm utility in uutils coreutils improperly handles Unicode encoding by converting all output lines using String::from_utf8_lossy(), causing invalid UTF-8 sequences to be replaced with the Unicode replacement character. This results in silent data corruption when processing binary or non-UTF-8 encoded files, diverging from GNU comm's behavior that preserves raw input bytes. The issue is classified under CWE-176 (Improper Handling of Unicode Encoding) and has a CVSS 3.3 (low) score, reflecting limited impact confined to data integrity.
Potential Impact
The vulnerability causes silent corruption of output data by replacing invalid UTF-8 byte sequences with a replacement character, which affects the integrity of output when comm is used on binary or legacy-encoded files. There is no impact on confidentiality or availability. No known exploits are reported in the wild.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, users should avoid using uutils coreutils comm for comparing binary or non-UTF-8 encoded files or use alternative tools such as GNU comm that preserve raw byte data.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- canonical
- Date Reserved
- 2026-04-02T12:58:56.087Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69e8f7ce19fe3cd2cdd00c1a
Added to database: 4/22/2026, 4:31:10 PM
Last enriched: 4/22/2026, 5:02:49 PM
Last updated: 4/23/2026, 2:29:56 AM
Views: 6
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