CVE-2026-56391

Crash and heap disclosure via multibyte length miscalculation

Published Jul 24, 2026 · Updated Jul 24, 2026

Out-of-bounds read in GNU Project coreutils 9.5 through 9.11 allows attackers to crash uniq via crafted multibyte input. The find_field() function repeatedly measures a fixed pointer instead of advancing through characters, then supplies the inflated byte length to memcmp. Exploitation requires a user or automated workflow to run uniq with -w and attacker-controlled input; consequences are a process crash and adjacent heap-memory exposure.

CVSS severity4.6
Medium
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in GNU Project coreutils 9.5 through 9.11 allows attackers to crash uniq via crafted multibyte input. The find_field() function repeatedly measures a fixed pointer instead of advancing through characters, then supplies the inflated byte length to memcmp. Exploitation requires a user or automated workflow to run uniq with -w and attacker-controlled input; consequences are a process crash and adjacent heap-memory exposure.

The record

CVE
CVE-2026-56391
Published
Jul 24, 2026
Updated
Jul 24, 2026
Vendor
The GnuPG Project
Product
coreutils
Classifications
CWE-125, T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 24, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=9.5 <=9.11

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

The GnuPG Project · coreutilsversion=9.5 <=9.11

Published CVSS scores

4.6CERT.PLCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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