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Fencer Intel
high 7.5

CVE-2026-59932 json

PhpSpreadsheet: Gnumeric reader unbounded gzip expansion causes memory exhaustion

published 3mo ago modified 19d ago also EUVD-2026-49952 , GHSA-2mrg-gjxq-2gvr

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 40%
public exploits
0
none known

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 Gnumeric reader reads attacker-supplied .gnumeric files into memory and, when the file starts with gzip magic bytes, calls gzdecode() on the full compressed contents without enforcing a decompressed-size limit. A very small compressed .gnumeric file can expand to data larger than the PHP memory limit and crash the process during Gnumeric::canRead() before the file is rejected or fully parsed. This is reachable through normal file-type detection and Gnumeric loading paths, so applications that accept attacker-controlled spreadsheet uploads can suffer denial of service. This issue has been fixed in versions 5.8.1, 3.10.7, 2.4.7, 2.1.18 and 1.30.6.

Patch / fix

  • packagist phpoffice/phpspreadsheet 1.30.6, 2.1.18, 2.4.7, 3.10.7, 5.8.1
  • phpoffice phpspreadsheet 1.30.6, 2.1.18, 2.4.7, 3.10.7, 5.8.1
  • phpspreadsheet_project phpspreadsheet 1.30.6, 2.1.18, 2.4.7, 3.10.7, 5.8.1

Is CVE-2026-59932 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
3mo ago

Exploit prediction

0.46% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-2mrg-gjxq-2gvr referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
packagist phpoffice/phpspreadsheet
>=4.0.0, <5.8.1
>=3.3.0, <3.10.7
>=2.2.0, <2.4.7
>=2.0.0, <2.1.18
<1.30.6
5.8.1
3.10.7
2.4.7
2.1.18
1.30.6

Affected products

  • PHPOffice PhpSpreadsheet

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption
  • CWE-409 Improper Handling of Highly Compressed Data (Data Amplification)

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.