CVE-2026-59931Public exploitNetwork attack vector

SSRF whitelist bypass via unvalidated HTTP redirect

Published Jul 28, 2026 · Updated Jul 28, 2026

SSRF in PhpSpreadsheet's WEBSERVICE() calculation path allows remote authenticated users to read internal HTTP resources through crafted XLSX files. Calculation/Web/Service.php validates only the initial host before webService() calls file_get_contents(), whose HTTP wrapper follows redirects without checking each target. Exploitation requires XLSX upload access, a configured domain whitelist, and formula calculation; responses up to 32,767 bytes can expose cloud metadata or internal services.

CVSS severity7.7
High
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in PhpSpreadsheet's WEBSERVICE() calculation path allows remote authenticated users to read internal HTTP resources through crafted XLSX files. Calculation/Web/Service.php validates only the initial host before webService() calls file_get_contents(), whose HTTP wrapper follows redirects without checking each target. Exploitation requires XLSX upload access, a configured domain whitelist, and formula calculation; responses up to 32,767 bytes can expose cloud metadata or internal services.

The record

CVE
CVE-2026-59931
Published
Jul 28, 2026
Updated
Jul 28, 2026
Vendor
PHPOffice
Product
PhpSpreadsheet
Classifications
CWE-918, T1552.005
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 28, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.30.6
  2. Affected versionversion=>= 2.0.0, < 2.1.18
  3. Affected versionversion=>= 2.2.0, < 2.4.7
  4. Affected versionversion=>= 3.3.0, < 3.10.7
  5. Affected versionversion=>= 4.0.0, < 5.8.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

PHPOffice · PhpSpreadsheetversion=< 1.30.6; version=>= 2.0.0, < 2.1.18; version=>= 2.2.0, < 2.4.7; version=>= 3.3.0, < 3.10.7; version=>= 4.0.0, < 5.8.1

Published CVSS scores

7.7GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
T1552.005Unsecured Credentials: Cloud Instance Metadata API

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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