CVE-2026-56392

Heap corruption via wrapped tab-stop allocation

Published Jul 24, 2026 · Updated Jul 24, 2026

Heap-based buffer overflow in GNU coreutils unexpand 9.11 and earlier allows local users to corrupt heap memory via large tab stops. The -t option's allocation calculation multiplies an attacker-controlled tab-stop value without detecting integer wraparound, creating an undersized heap buffer that subsequent writes exceed. Reachability requires running unexpand with a large attacker-provided -t value and crafted input; the demonstrated consequence is a crash, while a heap-write primitive depends on memory layout.

CVSS severity1.8
Low
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in GNU coreutils unexpand 9.11 and earlier allows local users to corrupt heap memory via large tab stops. The -t option's allocation calculation multiplies an attacker-controlled tab-stop value without detecting integer wraparound, creating an undersized heap buffer that subsequent writes exceed. Reachability requires running unexpand with a large attacker-provided -t value and crafted input; the demonstrated consequence is a crash, while a heap-write primitive depends on memory layout.

The record

CVE
CVE-2026-56392
Published
Jul 24, 2026
Updated
Jul 24, 2026
Vendor
The GnuPG Project
Product
coreutils
Classifications
CWE-122
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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=9.11

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

The GnuPG Project · coreutilsversion=0 <=9.11

Published CVSS scores

1.8CERT.PLCVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:N/VI:L/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-122Heap-based Buffer Overflow

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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