CVE-2026-18839: Integer Underflow (CVSS 2.2)

Description

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.

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CVSS v3.1 Score

2.2

LOW

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

EPSS — Exploit Prediction

0.0008

Probability of exploitation

0.00%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-191 CWE-191

References

Other References

https://access.redhat.com/security/cve/CVE-2026-18839 https://bugzilla.redhat.com/show_bug.cgi?id=2511010

Frequently Asked Questions

What is CVE-2026-18839? +

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. It has a CVSS v3.1 base score of 2.2 (LOW).

How severe is CVE-2026-18839? +

CVE-2026-18839 has a CVSS v3.1 score of 2.2 out of 10, rated LOW. This is a low-severity vulnerability with limited impact. The EPSS score is 0.0008, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-18839? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2026-18839