CVE-2026-18508

Published Aug 3, 2026

Last updated a month ago

CVSS medium 4.4

Overview

Description
A flaw was found in GNU tar. When extracting an archive with the --one-top-level option, hardlink targets are not confined to the designated top-level directory and may resolve relative to the extraction working directory. A crafted archive can create hardlinks that escape the intended boundary and, when combined with a preexisting symbolic link under the working directory, may allow writing outside that boundary during a single extraction.
Source
secalert@redhat.com
NVD status
Modified
Products
tar, openshift_container_platform, enterprise_linux

Risk scores

CVSS 3.1

Type
Secondary
Base score
4.4
Impact score
2.5
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
Severity
MEDIUM

Weaknesses

secalert@redhat.com
CWE-59

Social media

Hype score
Not currently trending

Configurations

Related CVEs

  1. A flaw was found in SSSD. A local user can trigger a Denial of Service (DoS) by exploiting a race condition in the autofs responder between asynchronous enumeration completion and map invalidation. By repeatedly sending concurrent map enumeration and invalidation requests, an attacker can cause memory to leak, leading to excessive memory consumption that can disrupt or crash the autofs service.•CVE-2026-104045
  2. A flaw was found in SSSD (System Security Services Daemon). When Identity Provider (IdP) authentication is enabled, pre-authentication requests retain state in memory without being cleared or timed out. A local attacker can repeatedly initiate authentication flows without completing them, causing unbounded memory consumption. This memory exhaustion can lead to a Denial of Service (DoS) by degrading or terminating SSSD authentication services.•CVE-2026-104046
  3. A flaw was found in SSSD. When configured to use Microsoft Entra ID, search inputs are not properly sanitized before being incorporated into directory query filters. A local user can exploit this vulnerability by submitting a crafted lookup request, manipulating the query logic to cause unauthorized information disclosure from the directory.•CVE-2026-104047
  4. A flaw was found in SSSD. In trust-enabled identity management environments, SSSD evaluates Host-Based Access Control (HBAC) rules by stripping domain qualifiers and comparing only short usernames. An authenticated user in a trusted domain who shares the same username as an authorized local account can bypass access policies and gain unauthorized access to protected services or hosts.•CVE-2026-104048
  5. A flaw was found in sssd. A local user can cause a Denial of Service (DoS) by exhausting the responder service's available file descriptors (system handles used for open connections). By opening and maintaining many concurrent connections to a responder socket while continuing to queue new connection attempts, an attacker can trigger an unthrottled retry loop. This condition leads to high CPU utilization and stalls the service, preventing legitimate identity and authentication requests from being processed.•CVE-2026-88252

References

Sources include official advisories and independent security research.