--- id: CVE-2026-56392 title: >- 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 summary: >- 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… severity: medium cvss: 6.1 cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H' cwe: - CWE-122 - CWE-787 vendor: gnu product: coreutils affected: - coreutils = 9.11 published: '2026-07-24' updated: '2026-10-02' sourceUpdated: '2026-10-02T13:57:53.010' source: NVD sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-56392' references: - url: 'https://cert.pl/en/posts/2026/07/CVE-2026-56391' label: cvd@cert.pl - url: 'https://git.savannah.gnu.org/cgit/coreutils.git/' label: cvd@cert.pl - url: >- https://git.savannah.gnu.org/cgit/coreutils.git/commit/?id=b60a159fdc5bfcf9988d3a4cb6f53abe8ad5d35d label: cvd@cert.pl - url: >- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-56392.json - url: 'https://access.redhat.com/security/cve/CVE-2026-56392' - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2506694' - url: 'https://www.cve.org/CVERecord?id=CVE-2026-56392' - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-56392' - url: 'https://access.redhat.com/errata/RHSA-2026:67886' - url: 'https://access.redhat.com/errata/RHBA-2026:47115' - url: 'https://access.redhat.com/errata/RHSA-2026:66403' - url: 'https://access.redhat.com/errata/RHSA-2026:72475' - url: 'https://access.redhat.com/errata/RHSA-2026:72395' - url: 'https://access.redhat.com/errata/RHSA-2026:72399' - url: 'https://access.redhat.com/errata/RHSA-2026:72476' - url: 'https://access.redhat.com/errata/RHSA-2026:72470' - url: 'https://access.redhat.com/errata/RHSA-2026:72394' - url: 'https://access.redhat.com/errata/RHSA-2026:40724' - url: 'https://access.redhat.com/errata/RHSA-2026:67956' - url: 'https://access.redhat.com/errata/RHSA-2026:71603' - url: 'https://access.redhat.com/errata/RHSA-2026:79357' tags: - nvd - csaf - vex - red-hat epss: 0.00186 epssPercentile: 0.08134 ingestedAt: '2026-10-02T14:20:32.554Z' patched: - enterprise_linux_baseos_v_10 - enterprise_linux_baseos_v_8 - enterprise_linux_baseos_v_9 - cert_manager_support_for_red_hat_openshift_release 1.20 - hardened_images - update_infrastructure 5 scores: nvd: 6.1 vendor: 4.4 --- ## Overview 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 ## Affected - `coreutils = 9.11` ## Remediation Refer to the linked advisories for vendor-supplied fixes and affected version ranges. ## Vendor advisories - **RHSA-2026:67886** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 10) · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:67886) - **RHBA-2026:47115** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 8) · released 2026-07-29 · [advisory](https://access.redhat.com/errata/RHBA-2026:47115) - **RHSA-2026:66403** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 9) · released 2026-09-10 · [advisory](https://access.redhat.com/errata/RHSA-2026:66403) - **RHSA-2026:72475** · Red Hat · fixed in: Cert Manager support for Red Hat OpenShift release 1.20 · released 2026-09-28 · [advisory](https://access.redhat.com/errata/RHSA-2026:72475) - **RHSA-2026:72395** · Red Hat · fixed in: Cert Manager support for Red Hat OpenShift release 1.20 · released 2026-09-28 · [advisory](https://access.redhat.com/errata/RHSA-2026:72395) - **RHSA-2026:72399** · Red Hat · fixed in: Cert Manager support for Red Hat OpenShift release 1.20 · released 2026-09-28 · [advisory](https://access.redhat.com/errata/RHSA-2026:72399) - **RHSA-2026:72476** · Red Hat · fixed in: Cert Manager support for Red Hat OpenShift release 1.20 · released 2026-09-28 · [advisory](https://access.redhat.com/errata/RHSA-2026:72476) - **RHSA-2026:72470** · Red Hat · fixed in: Cert Manager support for Red Hat OpenShift release 1.20 · released 2026-09-28 · [advisory](https://access.redhat.com/errata/RHSA-2026:72470) - **RHSA-2026:72394** · Red Hat · fixed in: Cert Manager support for Red Hat OpenShift release 1.20 · released 2026-09-28 · [advisory](https://access.redhat.com/errata/RHSA-2026:72394) - **RHSA-2026:40724** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-07-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:40724) - **RHSA-2026:67956** · Red Hat · fixed in: Red Hat Update Infrastructure 5 · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:67956) - **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat OpenShift Container Platform 4 · updated 2026-10-09 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-56392.json) - **RHSA-2026:79357** · Red Hat · fixed in: Red Hat Cost Management On-Premise 1 · released 2026-10-08 · [advisory](https://access.redhat.com/errata/RHSA-2026:79357)