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

tuxcare ALMALINUX9.2:CLSA-2026:1788268556: coreutils: Fix of CVE-2026-56392 (Moderate)

The remote MiracleLinux 9 host has packages installed that are affected by a vulnerability as referenced in the AXSA:2026-1880:05 advisory.

    * coreutils: GNU coreutils unexpand: Denial of Service via crafted tab stop values (CVE-2026-56392)

Tenable has extracted the preceding description block directly from the MiracleLinux 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 AlmaLinux 10 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALSA-2026:67886 advisory.

    * coreutils: GNU coreutils uniq: Denial of Service and information disclosure via out-of-bounds read with     multibyte input (CVE-2026-56391)
      * coreutils: GNU coreutils unexpand: Denial of Service via crafted tab stop values (CVE-2026-56392)

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

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

The remote RockyLinux 10 host has packages installed that are affected by multiple vulnerabilities as referenced in the RLSA-2026:67886 advisory.

    * coreutils: GNU coreutils uniq: Denial of Service and information disclosure via out-of-bounds read with     multibyte input (CVE-2026-56391)

    * coreutils: GNU coreutils unexpand: Denial of Service via crafted tab stop values (CVE-2026-56392)

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

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

The remote Oracle Linux 10 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2026-67886 advisory.

    - uniq: fix CVE-2026-56391 (RHEL-216794)
      - fix read overrun with -w

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

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

The remote Redhat Enterprise Linux 10 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:67886 advisory.

    The coreutils packages contain the GNU Core Utilities and represent a combination of the previously used     GNU fileutils, sh-utils, and textutils packages.

    Security Fix(es):

    * coreutils: GNU coreutils uniq: Denial of Service and information disclosure via out-of-bounds read with     multibyte input (CVE-2026-56391)

    * coreutils: GNU coreutils unexpand: Denial of Service via crafted tab stop values (CVE-2026-56392)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

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

The remote AlmaLinux 9 host has packages installed that are affected by a vulnerability as referenced in the ALSA-2026:66403 advisory.

    * coreutils: GNU coreutils unexpand: Denial of Service via crafted tab stop values (CVE-2026-56392)

Tenable has extracted the preceding description block directly from the AlmaLinux 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 RockyLinux 9 host has packages installed that are affected by a vulnerability as referenced in the RLSA-2026:66403 advisory.

    * coreutils: GNU coreutils unexpand: Denial of Service via crafted tab stop values (CVE-2026-56392)

Tenable has extracted the preceding description block directly from the RockyLinux 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 Oracle Linux 9 host has packages installed that are affected by a vulnerability as referenced in the ELSA-2026-664030 advisory.

    [8.32-41.0.1.el9_8.1]
    - clean up empty file if cp is failed [Orabug 15973168]

    [8.32-41.1]
    - unexpand: fix CVE-2026-56392 and related crashes (RHEL-216788)
      - fix direct.sh and unexpand/mb.sh tests
      - fix heap overflow with large tab stops
      - fix heap overflow when a wide blank overshoots a tab stop

Tenable has extracted the preceding description block directly from the Oracle 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 Redhat Enterprise Linux 9 host has packages installed that are affected by a vulnerability as referenced in the RHSA-2026:66403 advisory.

    The coreutils packages contain the GNU Core Utilities and represent a combination of the previously used     GNU fileutils, sh-utils, and textutils packages.

    Security Fix(es):

    * coreutils: GNU coreutils unexpand: Denial of Service via crafted tab stop values (CVE-2026-56392)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise 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 Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2026-104994 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

Tenable has extracted the preceding description block directly from the Unity 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.

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
348145	MiracleLinux 9 : coreutils-8.32-41.el9_8.1 (AXSA:2026-1880:05)	Nessus	Miracle Linux Local Security Checks	Local	low
346881	AlmaLinux 10 : coreutils (ALSA-2026:67886)	Nessus	Alma Linux Local Security Checks	Local	medium
346839	RockyLinux 10 : coreutils (RLSA-2026:67886)	Nessus	Rocky Linux Local Security Checks	Local	medium
346423	Oracle Linux 10 : coreutils (ELSA-2026-67886)	Nessus	Oracle Linux Local Security Checks	Local	medium
346281	RHEL 10 : coreutils (RHSA-2026:67886)	Nessus	Red Hat Local Security Checks	Local	medium
344846	AlmaLinux 9 : coreutils (ALSA-2026:66403)	Nessus	Alma Linux Local Security Checks	Local	low
344831	RockyLinux 9 : coreutils (RLSA-2026:66403)	Nessus	Rocky Linux Local Security Checks	Local	low
344784	Oracle Linux 9 : ELSA-2026-66403-0: / coreutils (ELSA-2026-664030)	Nessus	Oracle Linux Local Security Checks	Local	low
344639	RHEL 9 : coreutils (RHSA-2026:66403)	Nessus	Red Hat Local Security Checks	Local	low
341565	Unity Linux 20.1070a Security Update: coreutils (UTSA-2026-104994)	Nessus	Unity Linux Local Security Checks	Local	low
337983	Photon OS 5.0: Coreutils PHSA-2026-5.0-91-0960	Nessus	PhotonOS Local Security Checks	Local	low
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

Detections

Analytics

CVE-2026-56392

low

Tenable Plugins

Coming Soon

low

medium

medium

medium

medium

low

low

low

low

low

low

low

low

low

low

low