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

An update of the coreutils package has been released.

The remote Alibaba Cloud Linux 3 host has packages installed that are affected by a vulnerability as referenced in the ALINUX3-SA-2026:0241 advisory.

    Package updates are available for Alibaba Cloud Linux 3 that fix the following vulnerabilities:

    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     outofbounds 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

Tenable has extracted the preceding description block directly from the Alibaba Cloud Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The version of Tencent Linux installed on the remote TencentOS Server 3 host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the TSSA-2026:0812 advisory.

    Package updates are available for TencentOS Server 3 that fix the following vulnerabilities:

    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     outofbounds 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

Tenable has extracted the preceding description block directly from the Tencent Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote MiracleLinux 8 host has packages installed that are affected by a vulnerability as referenced in the AXBA:2026-1420:03 advisory.

  - 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 outofbounds 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 (CVE-2026-56392)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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 outofbounds 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 (CVE-2026-56392)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
334725	Photon OS 5.0: Coreutils PHSA-2026-5.0-92-0953	Nessus	PhotonOS Local Security Checks	Local	low
333571	Alibaba Cloud Linux 3 : 0241: coreutils (ALINUX3-SA-2026:0241)	Nessus	Alibaba Cloud Linux Local Security Checks	Local	low
333139	TencentOS Server 3: coreutils bug fix and enhancement update (Moderate) (TSSA-2026:0812)	Nessus	Tencent Local Security Checks	Local	low
331692	MiracleLinux 8 : coreutils-8.30-20.el8_10 (AXBA:2026-1420:03)	Nessus	Miracle Linux Local Security Checks	Local	low
329674	Linux Distros Unpatched Vulnerability : CVE-2026-56392	Nessus	Misc.	Local	low

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