How severe is CVE-2026-56392?

CVE-2026-56392 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability high.

Is CVE-2026-56392 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-56392?

CVE-2026-56392 affects Gnu Coreutils. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-56392?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2026-56392 published?

CVE-2026-56392 was published on 2026-07-24 and last updated on 2026-10-02.

CVE-2026-56392

CVE-2026-56392 is a medium-severity vulnerability in Gnu Coreutils with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-122.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v4: 1.8
EPSS exploit prediction: 0% (7th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-122
Affected product: Gnu Coreutils
Published: 2026-07-24
Last modified: 2026-10-02

Description

GNU coreutils unexpand is vulnerable to a heap-based buffer overflow due to an integer overflow during buffer allocation when processing large tab stop (-t) values. The multiplication used to calculate the allocation size can wrap around, resulting in an undersized buffer. When processing crafted input, subsequent writes exceed the allocated memory, leading to an out‑of‑bounds heap write. When running GNU coreutils unexpand with attacker-provided large tab stop (-t) arguments, this behavior leads to a crash and potentially achieve a heap write primitive depending on memory layout. This issue has been fixed in the commit b60a159fdc5bfcf9988d3a4cb6f53abe8ad5d35d

Frequently asked questions

What is CVE-2026-56392?: GNU coreutils unexpand is vulnerable to a heap-based buffer overflow due to an integer overflow during buffer allocation when processing large tab stop (-t) values. The multiplication used to calculate the allocation size can wrap around, resulting in an undersized buffer. When processing crafted input, subsequent writes exceed the allocated memory, leading to an out‑of‑bounds heap write. When running GNU coreutils unexpand with attacker-provided large tab stop (-t) arguments, this behavior leads to a crash and potentially achieve a heap write primitive depending on memory layout. This issue has been fixed in the commit b60a159fdc5bfcf9988d3a4cb6f53abe8ad5d35d
How severe is CVE-2026-56392?: CVE-2026-56392 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability high.
Is CVE-2026-56392 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-56392?: CVE-2026-56392 affects Gnu Coreutils. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-56392?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-56392 published?: CVE-2026-56392 was published on 2026-07-24 and last updated on 2026-10-02.

References

Affected products (1)

cpe:2.3:a:gnu:coreutils:9.11:*:*:*:*:*:*:*

More vulnerabilities in Gnu Coreutils

CVE-2015-4042 — Critical (CVSS 9.8): Integer overflow in the keycompare_mb function in sort.c in sort in GNU Coreutils through 8.23 might allow attackers to…
CVE-2015-4041 — High (CVSS 7.8): The keycompare_mb function in sort.c in sort in GNU Coreutils through 8.23 on 64-bit platforms performs a size…
CVE-2014-9471 — High (CVSS 7.5): The parse_datetime function in GNU coreutils allows remote attackers to cause a denial of service (crash) or possibly…
CVE-2017-18018 — High (CVSS 7.1): In GNU Coreutils through 8.29, chown-core.c in chown and chgrp does not prevent replacement of a plain file with a…
CVE-2026-56391 — Medium (CVSS 6.1): GNU coreutils uniq is vulnerable to an out‑of‑bounds read due to incorrect handling of multibyte input when the -w…
CVE-2024-0684 — Medium (CVSS 5.5): A flaw was found in the GNU coreutils "split" program. A heap overflow with user-controlled data of multiple hundred…

All CVEs affecting Gnu Coreutils →

Other CWE-122 (Heap-based Buffer Overflow) vulnerabilities

CVE-2026-10747 — Critical (CVSS 10.0): IBM MQ Appliance could allow a remote attacker to cause a denial of service or potentially execute arbitrary code due…
CVE-2026-46752 — Critical (CVSS 10.0): Redis Lua HEAP overflow in cjson library vulnerability in Apache Kvrocks. This issue affects Apache Kvrocks: from…
CVE-2026-24822 — Critical (CVSS 10.0): Out-of-bounds Write, Heap-based Buffer Overflow vulnerability in ttttupup wxhelper (src modules). This vulnerability is…
CVE-2025-23123 — Critical (CVSS 10.0): A malicious actor with access to the management network could execute a remote code execution (RCE) by exploiting a…
CVE-2022-34819 — Critical (CVSS 10.0): A vulnerability has been identified in SIMATIC CP 1242-7 V2 (All versions < V3.3.46), SIMATIC CP 1243-1 (All versions <…
CVE-2026-10858 — Critical (CVSS 9.9): IBM MQ for HPE NonStop 8.1.0 through 8.1.0.40 could allow an authenticated attacker to cause a denial of service or…

Browse all CWE-122 (Heap-based Buffer Overflow) vulnerabilities →