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Public proof of conceptFix available

CVE-2026-34839

A public proof of concept exists; no exploitation attested.

  • Published2026-04-21
  • Fixed in4.5.4
  • WeaknessCWE-200 · CWE-306 · CWE-942

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC
  1. 2026-04-2100:16CVE publishedNVD

Versions per branch

NVD · OSV
Nicolargo glances
BranchAffectedFixed in
4.5< 4.5.44.5.4

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As GitHub_M, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • nicolargo glances
    Affected
    • = < 4.5.4no fix stated

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-04-20

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • glancesUbuntu:Pro:20.04:LTSall versions · no fixed version listed
  • glancesUbuntu:Pro:18.04:LTSall versions · no fixed version listed
  • glancesUbuntu:Pro:16.04:LTSall versions · no fixed version listed
  • glancesUbuntu:26.10all versions · no fixed version listed
  • glancesUbuntu:26.04:LTSall versions · no fixed version listed
  • glancesUbuntu:25.10all versions · no fixed version listed
  • glancesUbuntu:24.04:LTSall versions · no fixed version listed
  • glancesUbuntu:22.04:LTSall versions · no fixed version listed

4 more package ranges on OSV.dev

Full record on NVD

Fix

  1. Update Nicolargo glances to 4.5.4

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • CISA-ADPSSVC decisionpoc2026-04-21
  • CNACVSS 4.07.7known since 2026-10-27
  • NVDCVSS 3.16.5read 2026-10-27
  • CNAweakness (CWE)CWE-200, CWE-306, CWE-942known since 2026-10-27
  • NVDweakness (CWE)CWE-306read 2026-10-27
  • FIRST EPSSEPSS score0.4 %2026-11-08
  • OSVaffected packages—
  • GitHub AdvisoriesadvisoryHIGH2026-04-21

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
CVSS 4.0 vector
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
Published
2026-04-21
Last Modified
2026-10-26
NVD status
Analyzed
GitHub Advisory
GHSA-gfc2-9qmw-w7vh

Frequently asked questions

What is CVE-2026-34839?

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.

Is CVE-2026-34839 actively exploited?

A proof-of-concept exploit exists for CVE-2026-34839, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2026-34839?

CVE-2026-34839 has a CVSS v3 base score of 6.5 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N.

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Sources for this record