CVE Intelligence
High SSRF

CVE-2026-59931 — PhpSpreadsheet: SSRF bypass via HTTP redirect in WEBSERVICE() domain whitelist

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 WEBSERVICE() domain whitelist can be bypassed via an HTTP redirect (SSRF). In Calculation/Web/Service.php, the webService() method validates a URL's host against the whitelist set via Spreadsheet::setDomainWhiteList(), then fetches content with file_get_contents($url, false, $ctx); because PHP's HTTP stream wrapper follows 301/302 redirects automatically (up to 20 hops) and the redirect target is never re-validated, an attacker who can trigger a redirect from a whitelisted domain can reach arbitrary URLs, including internal addresses. An attacker able to upload XLSX files to an application that uses setDomainWhiteList() and getCalculatedValue() can achieve a full-read SSRF, returning up to 32,767 bytes of the response body as a cell's calculated value, which enables exfiltration of cloud metadata (AWS/GCP/Azure credentials via http://169.254.169.254/), access to internal-only services, and internal port scanning (the port is not validated). This issue has been fixed in versions 5.8.1, 3.10.7, 2.4.7, 2.1.18, and 1.30.6.

Published Jul 28, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: GitHub_M

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.5% (30-day exploitation probability)+7
  • Technical severity (high)+6
  • CISA SSVC: exploitation "poc"+5

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.53%
ahead of 44% of scored CVEs · Oct 15, 2026
Affects
Phpoffice
Phpspreadsheet
CVSS base
7.7
High · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
Proof of concept
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Phpoffice Phpspreadsheet).
  2. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  3. Search available logs for exploit probes matching the vulnerability class (ssrf), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Phpoffice Phpspreadsheet version >= 4.0.0, < 5.8.1version >= 3.3.0, < 3.10.7version >= 2.2.0, < 2.4.7version >= 2.0.0, < 2.1.18version < 1.30.6 Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
7.7 CVSS 3.1 High 3.1 4.0 security-advisories@github.com via NIST National Vulnerability Database
7.7 CVSS 3.1 High — — GitHub_M via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N (score shown at the top: security-advisories@github.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-918 · Server-Side Request Forgery (SSRF)

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Monitor outbound requests from the server to internal IPs and cloud metadata endpoints.
web/proxy/WAF logsnetwork IDS/IPSegress traffic

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · phpoffice/phpspreadsheet
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 15, 2026
  • CVSS changed · 7.7
    Oct 15, 2026 · NIST National Vulnerability Database
  • Source status changed · → Deferred
    Oct 15, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 15, 2026 · NIST National Vulnerability Database
  • CVE published
    Jul 28, 2026 · GitHub_M

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

7 on the record

Elsewhere on this site

Phpoffice
every CVE for this vendor
SSRF
same class
CWE-918
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-59932 PhpSpreadsheet: Gnumeric reader unbounded gzip expansion causes memory exhaustion Jul 28, 2026
  • CVE-2026-59933 PhpSpreadsheet: XLS/OLE sector-chain self-loop causes memory exhaustion Jul 28, 2026
  • CVE-2026-45034 PhpSpreadsheet phar Wrapper Check Bypass Leading to Deserialization Risk Jun 22, 2026
  • CVE-2026-40863 PhpSpreadsheet: CPU Denial of Service via Unbounded Row Index in SpreadsheetML XML Reader May 12, 2026
  • CVE-2026-40902 PhpSpreadsheet: CPU Denial of Service via Unbounded Row Number in XLSX Row Dimensions May 12, 2026
  • CVE-2026-40296 PhpSpreadsheet vulnerable to XSS in HTML writer via custom number format codes May 6, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No fixed version, patch or mitigation documented.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-59931 is "PhpSpreadsheet: SSRF bypass via HTTP redirect in WEBSERVICE() domain whitelist", rated High. It affects Phpspreadsheet (Phpoffice); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.7 describes technical severity. EPSS 0.53% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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