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Fencer Vulns
low 3.3

CVE-2026-35346 json

uutils coreutils comm Silent Data Corruption via Lossy UTF-8 Normalization

published 2026-04-22 6 mo ago modified 2026-10-26 13 d ago also GHSA-6gcw-w7cp-94g9 , EUVD-2026-24978

cvss
3.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 7%
public exploits
0
none known

Summary

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.

Patch / fix

  • crates.io uu_comm 0.6.0
  • Uutils coreutils 0.6.0
  • rust-coreutils Debian 14 0.6.0-1

debian advisories DEBIAN-CVE-2026-35346

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-35346 updated cvss 3.3

rust-coreutils: comm: silent data corruption via lossy UTF-8 normalization

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
6 mo ago

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/uutils/coreutils/issues/10192 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 3.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
GitHub 3.1 3.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Affected packages

ecosystem package affected fixed in
crates.io uu_comm
<0.6.0
0.6.0

Affected products

  • Uutils coreutils

Classification

Weakness
  • CWE-176 Improper Handling of Unicode Encoding
  • CWE-116 Improper Encoding or Escaping of Output

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.