popt Integer Underflow in Help Formatting Causes DOS
CVE-2026-18839 Published on August 5, 2026

Popt-devel: popt-static: size_t underflow in singleoptionhelp
An integer underflow was found in the popt library when formatting help text for option tables that exceed the terminal width. A local user who can cause an application to print help under those conditions may cause that application to crash or fail to display help, resulting in a denial of service of the affected application.

NVD

Vulnerability Analysis

CVE-2026-18839 can be exploited with local system access, requires user interaction and a small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a small impact on availability.

Attack Vector:
LOCAL
Attack Complexity:
HIGH
Privileges Required:
LOW
User Interaction:
REQUIRED
Scope:
UNCHANGED
Confidentiality Impact:
NONE
Integrity Impact:
NONE
Availability Impact:
LOW

Timeline

Reported to Red Hat.

Made public. 1 day later.

Weakness Type

What is an Integer underflow Vulnerability?

The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result. This can happen in signed and unsigned cases.

CVE-2026-18839 has been classified to as an Integer underflow vulnerability or weakness.


Products Associated with CVE-2026-18839

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Affected Versions

rpm-software-management popt: Red Hat Enterprise Linux 10: Red Hat Enterprise Linux 6: Red Hat Enterprise Linux 7: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 9: Red Hat Hardened Images: Red Hat OpenShift Container Platform 4: