Linux: Use After Free
CVE-2024-46858 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.0 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 0e7814b028cd50b3ff79659d23dfa9da6a1e75e1, 3554482f4691571fc4b5490c17ae26896e62171c, 67409b358500c71632116356a0b065f112d7b707 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.59% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 0e7814b028cd50b3ff79659d23dfa9da6a1e75e1 or 3554482f4691571fc4b5490c17ae26896e62171c or 67409b358500c71632116356a0b065f112d7b707 or 6452b162549c7f9ef54655d3fb9977b9192e6e5b, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.1.111 or 6.6.52 or 6.10.11, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 00cfd77b9063dcdf3628a7087faba60de85a9cc8 up to, but not including, 0e7814b028cd50b3ff79659d23dfa9da6a1e75e1; 00cfd77b9063dcdf3628a7087faba60de85a9cc8 up to, but not including, 3554482f4691571fc4b5490c17ae26896e62171c; 00cfd77b9063dcdf3628a7087faba60de85a9cc8 up to, but not including, 67409b358500c71632116356a0b065f112d7b707; 00cfd77b9063dcdf3628a7087faba60de85a9cc8 up to, but not including, 6452b162549c7f9ef54655d3fb9977b9192e6e5b; 00cfd77b9063dcdf3628a7087faba60de85a9cc8 up to, but not including, 12134a652b0a10064844ea235173e70246eba6dc; 00cfd77b9063dcdf3628a7087faba60de85a9cc8 up to, but not including, b4cd80b0338945a94972ac3ed54f8338d2da2076; 5.10 | 0e7814b028cd50b3ff79659d23dfa9da6a1e75e1, 3554482f4691571fc4b5490c17ae26896e62171c, 67409b358500c71632116356a0b065f112d7b707, 6452b162549c7f9ef54655d3fb9977b9192e6e5b, 12134a652b0a10064844ea235173e70246eba6dc, b4cd80b0338945a94972ac3ed54f8338d2da2076 |
| Linux | Linux Kernel | 5.10 up to, but not including, 6.1.111; 6.2 up to, but not including, 6.6.52; 6.7 up to, but not including, 6.10.11; 6.11 | 6.1.111, 6.6.52, 6.10.11 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.1 | High | CNA |
| CVSS 3.1 | 7.0 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: mptcp: pm: Fix uaf in __timer_delete_sync There are two paths to access mptcp_pm_del_add_timer, result in a race condition: CPU1 CPU2 ==== ==== net_rx_action napi_poll netlink_sendmsg __napi_poll netlink_unicast process_backlog netlink_unicast_kernel __netif_receive_skb genl_rcv __netif_receive_skb_one_core netlink_rcv_skb NF_HOOK genl_rcv_msg ip_local_deliver_finish genl_family_rcv_msg ip_protocol_deliver_rcu genl_family_rcv_msg_doit tcp_v4_rcv mptcp_pm_nl_flush_addrs_doit tcp_v4_do_rcv mptcp_nl_remove_addrs_list tcp_rcv_established mptcp_pm_remove_addrs_and_subflows tcp_data_queue remove_anno_list_by_saddr mptcp_incoming_options mptcp_pm_del_add_timer mptcp_pm_del_add_timer kfree(entry) In remove_anno_list_by_saddr(running on CPU2), after leaving the critical zone protected by "pm.lock", the entry will be released, which leads to the occurrence of uaf in the mptcp_pm_del_add_timer(running on CPU1). Keeping a reference to add_timer inside the lock, and calling sk_stop_timer_sync() with this reference, instead of "entry->add_timer". Move list_del(&entry->list) to mptcp_pm_del_add_timer and inside the pm lock, do not directly access any members of the entry outside the pm lock, which can avoid similar "entry->x" uaf.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
Recent Use After Free vulnerabilities
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