Resource exhaustion in PhpSpreadsheet - CVE-2026-59933
Published: July 20, 2026
Vulnerability identifier: #VU138422
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-59933
CWE-ID: CWE-400
Exploitation vector: Remote access
Exploit availability:
Public exploit is available
Vulnerability details
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to application does not properly control consumption of internal resources within XLS/OLE sector-chain self-loop. A remote attacker can trigger resource exhaustion and perform a denial of service (DoS) attack.
Affected software
PhpSpreadsheet
How to mitigate CVE-2026-59933
Install updates from vendor's website.
PhpSpreadsheet - addressed in versions 1.30.6, 2.1.18, 2.4.7, 3.10.7, 5.8.1