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CVE-2026-59933· NVD / CVE Program· CNA GitHub_M

PhpSpreadsheet: XLS/OLE sector-chain self-loop causes memory exhaustion

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.

HighCVSS 7.5 · v3.1—No exploit Fix available

Noroxi analysis

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Published
Jul 28, 2026
Updated
Jul 30, 2026
EPSS
0.7% · 51th percentile
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Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.7%

CISA SSVC decision

Exploitation
proof of concept
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
7.5
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Affected systems

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • 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, < 1.30.6affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Packagistphpoffice/phpspreadsheetfrom 2.0.0 · before 2.1.182.1.18
Packagistphpoffice/phpspreadsheetfrom 2.2.0 · before 2.4.72.4.7
Packagistphpoffice/phpspreadsheetfrom 3.3.0 · before 3.10.73.10.7
Packagistphpoffice/phpspreadsheetfrom 4.0.0 · before 5.8.15.8.1
Packagistphpoffice/phpspreadsheetbefore 1.30.61.30.6

Same product

phpoffice: all records

Other highest-scoring records for the same primary product.

  • CVE-2018-19277securityScan() in PHPOffice PhpSpreadsheet through 1.5.0 allows a bypass of protection mechanisms for XXE via UTF-7 encoding in a .xlsx file
    37Monitor
  • CVE-2026-45034PhpSpreadsheet: File::prohibitWrappers bypass
    36Monitor
  • CVE-2026-34084PhpSpreadsheet SSRF and RCE via PHP stream wrappers in IOFactory::load
    36Monitor
  • CVE-2024-45291Path traversal and Server-Side Request Forgery in HTML writer when embedding images is enabled in PHPSpreadsheet
    35Monitor
  • CVE-2019-12331PHPOffice PhpSpreadsheet before 1.8.0 has an XXE issue.
    35Monitor
  • CVE-2025-54370PhpSpreadsheet vulnerable to SSRF when reading and displaying a processed HTML document in the browser
    34Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Packagist:phpoffice/phpspreadsheet1.30.6Package registry (OSV)
Packagist:phpoffice/phpspreadsheet2.1.18Package registry (OSV)
Packagist:phpoffice/phpspreadsheet2.4.7Package registry (OSV)
Packagist:phpoffice/phpspreadsheet3.10.7Package registry (OSV)
Packagist:phpoffice/phpspreadsheet5.8.1Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-599320 days apartPhpSpreadsheet: Gnumeric reader unbounded gzip expansion causes memory exhaustion
    30Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-400 · Uncontrolled Resource Consumption

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd-secondary

Root cause

Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.

The bug in code

The whole CWE-400 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
function expand(node) {  return node.children.map(expand);}

Fixed

ts
const MAX_DEPTH = 32;function expand(node, depth = 0) {  if (depth > MAX_DEPTH) throw new Error("too deep");  return node.children.map((c) => expand(c, depth + 1));}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records