CVE-2026-18839Hinoki check available

Application crash via help-width integer underflow

Published Aug 5, 2026 · Updated Aug 5, 2026

Integer underflow in popt 1.13 and later allows local users to crash applications by printing wide option tables in narrow terminals. The singleOptionHelp routine subtracts option widths from the terminal width in a size_t calculation, wrapping the available width when the table is wider. Exploitation requires local access, application help output, a sufficiently narrow terminal, and wide option entries; the bounded consequence is application failure or a crash.

CVSS severity2.2
Low
EPSS probability0.08%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Integer underflow in popt 1.13 and later allows local users to crash applications by printing wide option tables in narrow terminals. The singleOptionHelp routine subtracts option widths from the terminal width in a size_t calculation, wrapping the available width when the table is wider. Exploitation requires local access, application help output, a sufficiently narrow terminal, and wide option entries; the bounded consequence is application failure or a crash.

The record

CVE
CVE-2026-18839
Published
Aug 5, 2026
Updated
Aug 5, 2026
Vendor
389 Directory Server
Product
Red Hat Enterprise Linux 10
Classifications
CWE-191, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 5, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

389 Directory Server · Red Hat Enterprise Linux 10Affected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 7Affected versions are unavailable in this record.
389 Directory Server · Red Hat Hardened ImagesAffected versions are unavailable in this record.
RPM Software Management · poptversion=1.13 <*
389 Directory Server · Red Hat Enterprise Linux 9Affected versions are unavailable in this record.
389 Directory Server · Red Hat OpenShift Container Platform 4Affected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 8Affected versions are unavailable in this record.

Published CVSS scores

2.2Red HatCVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-191Integer Underflow (Wrap or Wraparound)
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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