Vulnerability-Lookup

RHSA-2026:40724

Vulnerability from csaf_redhat - Published: 2026-07-16 05:27 - Updated: 2026-07-27 12:00

Summary

Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update

Severity

Moderate

Notes

Topic: An update for Red Hat Hardened Images RPMs is now available.

Details: This update includes the following RPMs: coreutils: * coreutils-9.11-5.hum1 (aarch64, x86_64) * coreutils-common-9.11-5.hum1 (aarch64, x86_64) * coreutils-single-9.11-5.hum1 (aarch64, x86_64) * coreutils-9.11-5.hum1.src (src)

Terms of Use: This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Red Hat Inc. and provide a link to the original.

CVE-2026-56392

A flaw was found in GNU coreutils, specifically in the `unexpand` utility. This vulnerability, a heap-based buffer overflow, occurs due to an integer overflow when `unexpand` processes unusually large tab stop values provided by a local attacker. This can lead to an undersized memory buffer, allowing subsequent operations to write beyond its boundaries. Successful exploitation can cause the `unexpand` utility to crash, potentially resulting in a denial of service or enabling further memory manipulation.

4.4 (Medium)


                        
                          CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L

CWE-787 - Out-of-bounds Write

Affected products

Fixed 3 products

Product	Version	Remediation
Unresolved product id: Red Hat Hardened Images:coreutils-main@aarch64	—	Vendor Fix fix Workaround
Unresolved product id: Red Hat Hardened Images:coreutils-main@src	—	Vendor Fix fix Workaround
Unresolved product id: Red Hat Hardened Images:coreutils-main@x86_64	—	Vendor Fix fix Workaround

Threats

Impact Moderate

References

12 references

URL	Category
https://access.redhat.com/errata/RHSA-2026:40724	self
https://images.redhat.com/	external
https://access.redhat.com/security/cve/CVE-2026-56392	external
https://access.redhat.com/security/updates/classi…	external
https://security.access.redhat.com/data/csaf/v2/a…	self
https://access.redhat.com/security/cve/CVE-2026-56392	self
https://bugzilla.redhat.com/show_bug.cgi?id=2506694	external
https://www.cve.org/CVERecord?id=CVE-2026-56392	external
https://nvd.nist.gov/vuln/detail/CVE-2026-56392	external
https://cert.pl/en/posts/2026/07/CVE-2026-56391	external
https://git.savannah.gnu.org/cgit/coreutils.git/	external
https://git.savannah.gnu.org/cgit/coreutils.git/c…	external

JSON

To clipboard

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      "discovery_date": "2026-07-24T09:01:08.479352+00:00",
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          "text": "A flaw was found in GNU coreutils, specifically in the `unexpand` utility. This vulnerability, a heap-based buffer overflow, occurs due to an integer overflow when `unexpand` processes unusually large tab stop values provided by a local attacker. This can lead to an undersized memory buffer, allowing subsequent operations to write beyond its boundaries. Successful exploitation can cause the `unexpand` utility to crash, potentially resulting in a denial of service or enabling further memory manipulation.",
          "title": "Vulnerability description"
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          "category": "other",
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}

CVE-2026-56392 (GCVE-0-2026-56392)

Vulnerability from cvelistv5 – Published: 2026-07-24 07:44 – Updated: 2026-07-24 12:32 X_Open Source

Title

Heap-based Buffer Overflow in GNU coreutils

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, 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

Severity

1.8 (Low)


                        
                          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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-122 - Heap-based Buffer Overflow

Assigner

CERT-PL

References

3 references

URL	Tags
https://cert.pl/en/posts/2026/07/CVE-2026-56391	third-party-advisory
https://git.savannah.gnu.org/cgit/coreutils.git/	product
https://git.savannah.gnu.org/cgit/coreutils.git/c…	patch

Impacted products

1 product

Vendor	Product	Version
GNU	coreutils	Affected: 0 , ≤ 9.11 (custom)

Credits

Michał Majchrowicz (AFINE Team) Marcin Wyczechowski (AFINE Team)

Show details on NVD website

JSON

To clipboard

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

Action not permitted

RHSA-2026:40724

CVE-2026-56392 (GCVE-0-2026-56392)

Tags

Sightings

Nomenclature