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LibreOffice Calc EUVDEUVD-2026-92418

| CVE-2026-63267 MEDIUM
Server-Side Request Forgery (SSRF) (CWE-918)
2026-10-05 Document Fdn. GHSA-2r33-w77m-6p5h
6.7
CVSS 4.0 · Vendor: Document Fdn.
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Craft spreadsheet with external CSV link
  2. Delivery
    Deliver document to victim
  3. Exploit
    Victim opens file in Calc
  4. Execution
    Link auto-fetched: local file read or outbound request
  5. Impact
    Sensitive data disclosed to attacker host

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V4 - API and Web Service URL allowlisting, SSRF prevention
MITRE ATT&CK

2 techniques across 2 tactics: Initial Access, Credential Access

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Exploitation requires the victim to open an attacker-crafted Calc document in which a cell range is linked to an external CSV data source. On affected (pre-fix) versions this external data link was fetched automatically during document load, bypassing the standard link-update confirmation that governs other links - so no victim click beyond opening the file is needed. Limiting factors: the attack is local and interaction-gated (UI:P) - the attacker must deliver the malicious document and the victim must open it; it does not affect integrity or availability (VI:N/VA:N), and fixed versions neutralize it by placing external data links under the same link-update control as other links.

Impact

This is a moderate, user-interaction-gated information-disclosure/SSRF flaw rather than a top-priority emergency. The vendor CVSS 4.0 vector (AV:L/AC:L/PR:L/UI:P/VC:H/SC:H) describes an attack that requires the victim to open an attacker-supplied spreadsheet, so there is no remote-unauthenticated mass-exploitation path; the high score is driven by the dual confidentiality impact (local file read on the victim system plus SSRF to an attacker-chosen host). No EPSS score, CISA KEV listing, or public POC was supplied in the intelligence, so exploitation status is 'no public exploit identified at time of analysis' - this is a disclosed-and-patched vendor-reported issue, not one with evidence of active abuse. One conflict to verify: the vector sets PR:L (implying some privilege/authentication), yet opening a document normally requires no privileges - opening an untrusted file is a user-interaction event, not an authentication event, so PR:N/UI:R is arguably more accurate; verify the intended privilege model with the vendor advisory. Overall: patch in normal maintenance cadence, prioritized by the fact that LibreOffice is extremely widely deployed and malicious-document delivery (email/download) is a realistic social-engineering vector.

Exploit ScenarioDerived

An attacker crafts a LibreOffice Calc spreadsheet containing a cell range linked to an external CSV data source and emails or shares it with a victim. When the victim opens the document, the affected version automatically fetches the external link - reading a local file path into the sheet (disclosing its contents back to a document the attacker may later recover) or issuing an HTTP request to an attacker-controlled host (SSRF/beaconing). No public exploit code was identified in the provided data, but crafting the malicious link is trivial and requires no special tooling.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 05, 2026

LibreOffice Calc on affected versions automatically fetched external CSV data links embedded in a spreadsheet while the document loaded, so an attacker-crafted Calc file could read a local file into a sheet or force a request to a host of the document author's choosing (SSRF, CWE-918). Exploitation is local and interaction-gated - the attacker must deliver the malicious document and the victim must open it - and the flaw affects confidentiality only, with no impact on integrity or availability. No public exploit code and no confirmed active exploitation were identified at time of analysis; the vendor addressed it by placing external data links under the same link-update control that governs other spreadsheet links.

RemediationAI

Upgrade LibreOffice Calc to a vendor-fixed release; the vendor advisory at https://www.libreoffice.org/about-us/security/advisories/cve-2026-63267 identifies the patched builds, and the fix itself brings external data links under the same link-update control as other spreadsheet links, so the automatic fetch on load no longer occurs - no exact fix version is stated in the supplied data, so confirm the version on the advisory before deploying. Where immediate upgrade is not possible, set the link-update behavior to never update automatically (Tools > Options > LibreOffice Calc > General > "Update links when opening" set to Never), which prevents the on-load fetch; the trade-off is that legitimate external data links in spreadsheets will stop refreshing, so dynamic workbooks must be opened with links updated manually via Edit > Links once the source is trusted. Organizations that must handle untrusted documents can additionally open them in a sandboxed or isolated environment with network egress restricted and local filesystem access limited to the import path, which blunts both the file-read and the outbound-request variants at the cost of extra operational overhead; blocking egress alone still leaves local file disclosure possible, so combine it with the link-update setting rather than relying on it exclusively.

Affected VersionsENISA

libreoffice 26.2 << 26.2.5

Affected Packages

euvd libreoffice_26_2 fix: 26.2.5

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The issue is an instance of CWE-918 (Server-Side Request Forgery) realized inside LibreOffice Calc's external-data-link feature. Calc allows a cell range to be bound to an external data source - in this case a CSV file - and that binding is persisted in the ODF spreadsheet document itself. On affected builds the external data link was fetched during document load without passing through the application's normal link-update confirmation, so the document effectively controlled both the target of the retrieval and the timing of it. That yields a confidentiality-only primitive: a file:// target lets a crafted document pull local file content into the sheet, while an http(s) target makes the client issue a request to an arbitrary host, which can be used for SSRF-style probing or exfiltration. The assessed CVSS:3.1 vector (AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N) frames this as a local, victim-open-gated attack with scope change and high confidentiality impact, while the vendor's CVSS:4.0 vector (AV:L/AC:L/AT:N/PR:L/UI:P/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N) likewise scores it 6.7 with low privileges and partial user interaction; both agree the attack is bounded by the need to open a malicious document. Note the divergence on privileges (PR:N in the assessment versus PR:L/UI:P in the CVSS 4.0 vector): authentication requirements are not confirmed as a binary from the conflicting vectors, but no credentials are consumed and the practical prerequisite is the victim opening the file. The fix is architectural rather than a parser patch - external data links are moved under the same link-update control used for all other links in a spreadsheet, restoring the confirmation gate the feature had bypassed.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (Document Fdn.) PRIMARY 6.7 MEDIUM
CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N
vuln.today AI 6.3 MEDIUM

Requires opening an attacker-supplied document (AV:L/UI:R) with no prior privilege (PR:N); SSRF/file-read reaches beyond the app boundary (S:C) disclosing data (C:H) with no integrity or availability impact.

3.1 AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N
4.0 AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N
SUSE 5.5 MEDIUM
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Red Hat 5.5 MEDIUM

Primary rating from Vendor (Document Fdn.).

CVSS VectorVendor: Document Fdn.

Attack Vector
Local
Attack Complexity
Low
Attack Requirements
None
Privileges Required
Low
User Interaction
Passive
Vulnerable system: Confidentiality
High
Vulnerable system: Integrity
None
Vulnerable system: Availability
None
Subsequent system: Confidentiality
High
Subsequent system: Integrity
None
Subsequent system: Availability
None

Lifecycle Timeline

2
Patch available
Oct 05, 2026 - 13:16 EUVD
CVE Published
Oct 05, 2026 - 11:17 cve.org
MEDIUM 6.7

DescriptionCVE.org

LibreOffice Calc can link a cell range to an external csv data source, and the link is saved in the document. Such a link was fetched while the document loaded, so opening a document could read a local file into the sheet, or make a request to a host of the document's choosing. In fixed versions external data links are updated under the same link update control as other links in a spreadsheet.

Threat Intelligence Overview

EPSS Score
0.1%
Top 99% exploitable
Prevalence
High
free office suite, default on many Linux distros and widely used cross-platform
Data Quality
5 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.1%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation
None
System Exposure· derived
Small
Automatable
No
Human Impact· derived
High
Technical Impact
Partial

Priority Score

34
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +34
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Server-Side Request Forgery exploits applications that fetch remote resources based on user-supplied URLs.

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Vendor StatusVendor

SUSE

Severity: Moderate
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise Module for Package Hub 15 SP7 Affected
SUSE Linux Enterprise Server 15 SP7 Affected
SUSE Linux Enterprise Server for SAP Applications 15 SP7 Affected
SUSE Linux Enterprise Workstation Extension 15 SP7 Affected

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