CVE-2026-58205: JeromeDevome GRR advisory

Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.

What it is

GRR is a resource management and reservation application. Prior to version 4.5.0, `maj.php` reflects the `forcemaj` parameter without adequate escaping when installation files remain accessible. Removal of these files is not automatic. An attacker can craft a URL that executes arbitrary JavaScript in a victim’s browser when the victim accesses it. This reflected cross-site scripting can enable phishing, redirection to malicious sites, cookie theft and session hijacking because the authentication cookie is not `HttpOnly`. This issue is fixed in version 4.5.0.

Description quoted from the CVE record (assigned by GitHub_M, published 2026-10-27).

Weakness: CWE-79: Improper Neutralization of Input During Web Page Generation (‘Cross-site Scripting’)

How it can be exploited

Exploitable over the network with low attack complexity needing no privileges and a user must take an action. Impact: confidentiality high, integrity high, availability none. CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

CISA assessment (SSVC): CISA has no evidence of exploitation. Automatable: no. Technical impact: partial.

Public exploit evidence (Exploit Observer)

VEDAS cluster: VEDAS:DOWNWINDDESSERT

Exploit Observer links 5 pieces of public exploit code or detection modules that name this CVE or one of its aliases.

Exploit code and modules (5)

Code that names this CVE. A repository can be a working exploit, a scanner, a fake or malware; read it before running anything.

Vulnerability databases and vendor advisories (1)

Catalogue entries, not exploit evidence.

Vulnerability database or vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-58205

2 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.

VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.

Live scores

EPSS: 0.003
low predicted chance of attack
VEDAS: 0.988
strong exploit evidence
On CISA KEV: Not listed
Detection rule: Nuclei · Suricata

Who is affected

Product	Affected	Not affected
JeromeDevome GRR	version < 4.5.0	Not stated

Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.

How to fix it

No fixed version or vendor advisory is listed in the CVE record yet. Watch the vendor’s security page.

How to detect it

Nuclei template (active check)

GRR < 4.5.0 - Reflected Cross-Site Scripting (maj.php forcemaj)
GRR (Gestion et Reservation de Ressources) before 4.5.0 reflects the ‘forcemaj’ request parameter in the installation/update script installation/maj.php without adequate output escaping when the installation files remain accessible (their removal is not automatic). The value of forcemaj is assigned to $version_depart and echoed directly into the HTML response, so an unauthenticated attacker can craft a URL that executes arbitrary JavaScript in a victim’s browser. This template requests installation/maj.php with an inert marker payload in forcemaj and confirms the issue when the payload is reflected unencoded in an HTML (text/html) 200 response.

Name and description quoted from the template, written by VEDAS.

The template sends 1 request (GET /installation/maj.php?forcemaj=vedasINJ58205%22%3E%3Csvg/onload=ale...); it decides using status, word matchers. Severity in the template: medium. Marked as not yet verified against a live vulnerable target.

Run it against a host you own or are authorised to test:

bash

nuclei -u https://your-host -t CVE-2026-58205.yaml

Show the template (49 lines)

yaml

id: CVE-2026-58205

info:
  name: "GRR < 4.5.0 - Reflected Cross-Site Scripting (maj.php forcemaj)"
  author: vedas-arpsyndicate
  severity: medium
  description: |
    GRR (Gestion et Reservation de Ressources) before 4.5.0 reflects the
    'forcemaj' request parameter in the installation/update script
    installation/maj.php without adequate output escaping when the installation
    files remain accessible (their removal is not automatic). The value of
    forcemaj is assigned to $version_depart and echoed directly into the HTML
    response, so an unauthenticated attacker can craft a URL that executes
    arbitrary JavaScript in a victim's browser. This template requests
    installation/maj.php with an inert marker payload in forcemaj and confirms the
    issue when the payload is reflected unencoded in an HTML (text/html) 200
    response.
  reference:
    - https://www.exploit.observer/?keyword=CVE-2026-58205&match=exact
    - https://subdomain.center/?engine=ammonites&keyword=grr&match=exact
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
    cve-id: CVE-2026-58205
    cwe-id: CWE-79
  metadata:
    verified: false
  tags: cve,cve2026,xss,grr,reflected

http:
  - raw:
      - |
        GET /installation/maj.php?forcemaj=vedasINJ58205%22%3E%3Csvg/onload=alert(document.domain)%3E HTTP/1.1
        Host: {{Hostname}}

    matchers-condition: and
    matchers:
      - type: word
        part: body
        words:
          - "vedasINJ58205\"><svg/onload=alert(document.domain)>"

      - type: word
        part: content_type
        words:
          - "text/html"

      - type: status
        status:
          - 200

CVE-2026-58205.yaml on GitHub

Suricata rules (network detection)

1 rule that alert on traffic matching this exploit: VEDAS CVE-2026-58205 GRR - maj.php forcemaj Reflected XSS. Add them to your Suricata rule set and reload.

Show the rules

suricata

# CVE-2026-58205 - GRR < 4.5.0 reflected XSS: installation/maj.php echoes the 'forcemaj'
# request parameter into the HTML response without escaping (when installation files remain
# accessible), so an unauthenticated attacker can reflect script into a victim's browser.
# This matches a request to maj.php whose forcemaj value carries an HTML/script payload.
alert http $EXTERNAL_NET any -> $HTTP_SERVERS $HTTP_PORTS (msg:"VEDAS CVE-2026-58205 GRR - maj.php forcemaj Reflected XSS"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/installation/maj.php"; nocase; fast_pattern; content:"forcemaj="; nocase; pcre:"/forcemaj=[^&]*(?:%3c|<)\s*(?:svg|script|img|iframe|body|on\w+\s*(?:%3d|=))/i"; classtype:web-application-attack; reference:cve,CVE-2026-58205; reference:url,https://www.exploit.observer/?keyword=CVE-2026-58205&match=exact; reference:url,https://subdomain.center/?engine=ammonites&keyword=grr&match=exact; sid:1098600; rev:1;)

CVE-2026-58205.rules on GitHub

References

Other references

https://github.com/JeromeDevome/GRR/security/advisories/GHSA-r6x2-w38j-vvq2 (x_refsource_CONFIRM)
https://github.com/JeromeDevome/GRR/commit/4ef77f91818215c1f8e0f06023d89257dfd61c68 (x_refsource_MISC)
https://github.com/JeromeDevome/GRR/tree/v4.5.0 (x_refsource_MISC)

Other databases

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, cve-scores (EPSS and VEDAS), Exploit Observer, vedas-signatures. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.