Skip to main content
No exploitation reportedFix available

CVE-2026-56392

Heap-based Buffer Overflow in GNU coreutils

No exploitation reported by the sources we read.

  • Published2026-07-24
  • WeaknessCWE-122

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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

Timeline

dates in UTC
  1. 2026-07-2409:16CVE publishedNVD

Versions per branch

NVD
Gnu coreutils
BranchAffectedFixed in
9.11= 9.11no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As CERT-PL, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • GNU coreutilsother versions: not affected
    Affected
    • ≤ 9.11no fix statedcustom

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-07-24

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • coreutilsTuxCare:AlmaLinux:9.6all versions · fixed in 8.32-39.el9.tuxcare.els2and 2 other packages
  • coreutilsTuxCare:AlmaLinux:9.2all versions · fixed in 8.32-34.el9.tuxcare.els2and 2 other packages
  • coreutilsRocky Linux:10all versions · fixed in 0:9.5-8.el10_2.1
  • coreutilsRocky Linux:9all versions · fixed in 0:8.32-41.el9_8.1
  • coreutilsRed Hat:hummingbird:1all versions · fixed in 0:9.11-5.hum1and 2 other packages
  • coreutilsRed Hat:enterprise_linux:10.2all versions · fixed in 0:9.5-8.el10_2.1and 4 other packages
  • coreutilsRed Hat:enterprise_linux:9::baseosall versions · fixed in 0:8.32-41.el9_8.1and 4 other packages
  • coreutilsRed Hat:enterprise_linux:8::baseosall versions · fixed in 0:8.30-20.el8_10and 5 other packages

11 more package ranges on OSV.dev

Vendor advisories

  • CVE-2026-56392 Red Hat Product Security112 products fixed · 6 known affected

    coreutils: GNU coreutils unexpand: Denial of Service via crafted tab stop values

    coreutils as a component of Red Hat Enterprise Linux 6 · coreutils-libs as a component of Red Hat Enterprise Linux 6 · coreutils.src as a component of Red Hat Enterprise Linux 6 · +3 more

  • RHSA-2026:81201 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: Cost Management Metrics Operator Update

  • RHSA-2026:79357 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat Cost Management On-Premise container image update

  • RHSA-2026:72476 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.20.1

  • RHSA-2026:72475 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.20.1

  • RHSA-2026:72470 Red Hat Product Security8 products fixed

    Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.20.1

9 more advisories

Full record on NVD

Fix

  1. Vendor fix Red Hat Product Security RHSA-2026:81201 · 4 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://docs.openshift.com/container-platform/latest/operators/admin/olm-upgrading-operators.html
  2. Vendor fix Red Hat Product Security RHSA-2026:79357 · 1 productThe container image provided by this update can be downloaded from the Red Hat container registry at registry.redhat.io using the "podman pull" command.
  3. Vendor fix Red Hat Product Security RHSA-2026:72476 · 4 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. The steps to apply the upgraded images are different depending on the installation plan approval policy you used when installing the cert-manager Operator for Red Hat OpenShift. - If t…
  4. Vendor fix Red Hat Product Security RHSA-2026:71603 · 1 productThe container images provided by this release, apart from the installer, should be deployed using rhui-installer utility. See the official documentation for more details.
  5. Vendor fix Red Hat Product Security RHSA-2026:67886 · 21 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  6. Vendor fix Red Hat Product Security RHSA-2026:40724 · 7 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H
CVSS 4.0 vector
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Published
2026-07-24
Last Modified
2026-10-24
NVD status
Analyzed
GitHub Advisory
GHSA-g24f-m2hx-pfgx

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

Is CVE-2026-56392 actively exploited?

Active exploitation of CVE-2026-56392 has not been confirmed. Its EPSS score was 0.2% on 2026-11-09, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-56392?

CVE-2026-56392 has a CVSS v3 base score of 6.1 (MEDIUM severity), with vector string CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H.

Running coreutils? Hear about its next vulnerability

Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

Get alerts for this productCISA KEV additions, November 2026Search CVEs

No credit card required · No monthly cap on website lookups · 250 API requests/month

Go further

Related vulnerabilities

Same product first, then the same vendor advisory and the same publication week.

Back to CVE Database

Sources for this record