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Response snapshot Oct 27, 2026, 04:12 UTC

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VulnerabilityCVE-2026-34839

Glances is an open-source system cross-platform monitoring tool.

Glances is an open-source system cross-platform monitoring tool. Prior to version 4.5.

At a glance

Exploited
Not known
Severity
7.7 High (CVSS 4.0)
Chance of exploitation
0.4% in the next 30 days
Sources
2 independent sources

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-34839 (opens a new tab)

What happened

Glances is an open-source system cross-platform monitoring tool. Prior to version 4.5.4, the Glances web server exposes a REST API (`/api/4/*`) that is accessible without authentication and allows cross-origin requests from any origin due to a permissive CORS policy (`Access-Control-Allow-Origin: *`).

This allows a malicious website to read sensitive system information from a running Glances instance in the victim’s browser, leading to cross-origin data exfiltration. While a previous advisory exists for XML-RPC CORS issues, this report demonstrates that the REST API (`/api/4/*`) is also affected and exposes significantly more sensitive data. Version 4.5.4 patches the issue.

Scores and how they were measured

CVSS base severity

7.7

Version 4.0As of

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

0.4%

Scored Percentile 34.8%

Model and measurement source (opens a new tab)

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    NVD CVE-2026-34839 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    Vendor advisory (via NVD references) (opens a new tab)

    The vendor advisory referenced by the CVE record, for affected versions and fixes.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  4. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  5. Primary source

    FIRST measured EPSS score (opens a new tab)

    Measured EPSS probability and percentile for CVE-2026-34839, scored 2026-10-26. This is a model estimate, not proof of exposure.

    Published Checked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 26). Glances is an open-source system cross-platform monitoring tool. (CVE-2026-34839). https://kevwire.com/record/CVE-2026-34839

MLA

"Glances is an open-source system cross-platform monitoring tool. (CVE-2026-34839)." KEVWire, 26 Oct. 2026, kevwire.com/record/CVE-2026-34839.

Chicago

KEVWire. "Glances is an open-source system cross-platform monitoring tool. (CVE-2026-34839)." Last modified October 26, 2026. https://kevwire.com/record/CVE-2026-34839.

Evidence summary (plain text)

Glances is an open-source system cross-platform monitoring tool. (Apr 21, 2026).
Glances is an open-source system cross-platform monitoring tool. Prior to version 4.5.4, the Glances web server exposes a REST API (`/api/4/*`) that is accessible without authentication and allows cross-origin requests from any origin due to a permissive CORS policy (`Access-Control-Allow-Origin: *`). This allows a malicious website to read sensitive system information from a running Glances instance in the victim’s browser, leading to cross-origin data exfiltration. While a previous advisory exists for XML-RPC CORS issues, this report demonstrates that the REST API (`/api/4/*`) is also affected and exposes significantly more sensitive data. Version 4.5.4 patches the issue.
CVSS 7.7 (version 4.0; evidence as of Oct 26, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-34839).
EPSS 0.4% for the following 30 days, scored Oct 26, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2026-34839&date=2026-10-26).
Sources:
NVD CVE-2026-34839: https://nvd.nist.gov/vuln/detail/CVE-2026-34839
Vendor advisory (via NVD references): https://github.com/nicolargo/glances/security/advisories/GHSA-gfc2-9qmw-w7vh
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-26T20:37:18.143Z&lastModEndDate=2026-10-26T22:10:56.995Z&resultsPerPage=500&startIndex=1500
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-26T20:05:59.720Z&lastModEndDate=2026-10-26T21:35:56.549Z&resultsPerPage=500&startIndex=1000
FIRST measured EPSS score: https://api.first.org/data/v1/epss?cve=CVE-2026-34839&date=2026-10-26
Record ID: CVE-2026-34839.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 27, 2026, 01:40 UTC. Ingestion is not an independent editorial investigation.

NVD status: Analyzed. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

Record JSON

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Record details

Record detail