CVE-2026-59933 (GCVE-0-2026-59933)

Vulnerability from cvelistv5 – Published: 2026-07-28 17:29 – Updated: 2026-07-28 17:57
VLAI
Title
PhpSpreadsheet: XLS/OLE sector-chain self-loop causes memory exhaustion
Summary
PhpSpreadsheet is a pure PHP library for reading and writing spreadsheet files. In versions 4.0.0 through 5.8.0, 3.3.0 through 3.10.6, 2.2.0 through 2.4.6, 2.0.0 through 2.1.17, and all releases up to and including 1.30.5, the OLE reader follows sector chains from attacker-controlled XLS/OLE metadata without detecting cycles or enforcing a maximum chain length. A tiny malformed .xls/OLE file can set the small-block depot sector chain to point back to itself. During normal XLS detection, OLERead::read() appends the same sector data repeatedly until the PHP process exhausts memory. This is reachable from Reader\Xls::canRead() and therefore from automatic spreadsheet type detection. Applications that accept attacker-controlled spreadsheet uploads can suffer denial of service from a very small file. This issue has been fixed in versions 5.8.1, 3.10.7, 2.4.7, 2.1.18 and 1.30.6.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: poc Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-07-28 17:57 UTC
CWE
  • CWE-400 - Uncontrolled Resource Consumption
  • CWE-835 - Loop with Unreachable Exit Condition ('Infinite Loop')
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7838 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
PHPOffice PhpSpreadsheet Affected: >= 4.0.0, < 5.8.1
Affected: >= 3.3.0, < 3.10.7
Affected: >= 2.2.0, < 2.4.7
Affected: >= 2.0.0, < 2.1.18
Affected: < 1.30.6
guessed Create a notification for this product.
Show details on NVD website
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}



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  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

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    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.