CVE-2026-18839 Popt-devel: popt-static: size_t underflow in singleoptionhelp
A local attacker can cause a denial of service in applications using the popt library by triggering an integer underflow during help text formatting.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-18839?
CVE-2026-18839 is a low-severity vulnerability in Red Hat Enterprise Linux 10, published on 5 Aug 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official 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.
Weakness: CWE-191
Which versions are affected by CVE-2026-18839?
Linux distribution packages (3)
popt Red Hat:hummingbird:1 | All versions | 0:1.19-11.2.hum1 |
popt-devel Red Hat:hummingbird:1 | All versions | 0:1.19-11.2.hum1 |
popt-static Red Hat:hummingbird:1 | All versions | 0:1.19-11.2.hum1 |
How do I fix CVE-2026-18839?
Apply the vendor's patch.
Is CVE-2026-18839 being exploited?
There is no known exploitation of CVE-2026-18839 in the wild and no public exploit code.
Sources
Also known as AZL-94511, AZL-94668, DEBIAN-CVE-2026-18839, ECHO-3ba8-d639-d262, GHSA-8fjx-p4xg-vgp8, OESA-2026-4392 and 5 more.