Linux: Use After Free
CVE-2024-26793 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.8 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 01129059d5141d62fae692f7a336ae3bc712d3eb, ec92aa2cab6f0048f10d6aa4f025c5885cb1a1b6, e668b92a3a01429923fd5ca13e99642aab47de69 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 0.29% 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 01129059d5141d62fae692f7a336ae3bc712d3eb or ec92aa2cab6f0048f10d6aa4f025c5885cb1a1b6 or e668b92a3a01429923fd5ca13e99642aab47de69 or 9376d059a705c5dfaac566c2d09891242013ae16, whichever matches your release line, or a later version.
- Update Linux Kernel to 4.19.309 or 5.4.271 or 5.10.212 or 5.15.151, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 459aa660eb1d8ce67080da1983bb81d716aa5a69 up to, but not including, 01129059d5141d62fae692f7a336ae3bc712d3eb; 459aa660eb1d8ce67080da1983bb81d716aa5a69 up to, but not including, ec92aa2cab6f0048f10d6aa4f025c5885cb1a1b6; 459aa660eb1d8ce67080da1983bb81d716aa5a69 up to, but not including, e668b92a3a01429923fd5ca13e99642aab47de69; 459aa660eb1d8ce67080da1983bb81d716aa5a69 up to, but not including, 9376d059a705c5dfaac566c2d09891242013ae16; 459aa660eb1d8ce67080da1983bb81d716aa5a69 up to, but not including, abd32d7f5c0294c1b2454c5a3b13b18446bac627; 459aa660eb1d8ce67080da1983bb81d716aa5a69 up to, but not including, 93dd420bc41531c9a31498b9538ca83ba6ec191e; 459aa660eb1d8ce67080da1983bb81d716aa5a69 up to, but not including, 5366969a19a8a0d2ffb3d27ef6e8905e5e4216f8; 459aa660eb1d8ce67080da1983bb81d716aa5a69 up to, but not including, 616d82c3cfa2a2146dd7e3ae47bda7e877ee549e; and 1 more ranges | 01129059d5141d62fae692f7a336ae3bc712d3eb, ec92aa2cab6f0048f10d6aa4f025c5885cb1a1b6, e668b92a3a01429923fd5ca13e99642aab47de69, 9376d059a705c5dfaac566c2d09891242013ae16, abd32d7f5c0294c1b2454c5a3b13b18446bac627, 93dd420bc41531c9a31498b9538ca83ba6ec191e |
| Linux | Linux Kernel | 4.7 up to, but not including, 4.19.309; 4.20 up to, but not including, 5.4.271; 5.5 up to, but not including, 5.10.212; 5.11 up to, but not including, 5.15.151; 5.16 up to, but not including, 6.1.81; 6.2 up to, but not including, 6.6.21; 6.7 up to, but not including, 6.7.9; 6.8 | 4.19.309, 5.4.271, 5.10.212, 5.15.151, 6.1.81, 6.6.21 |
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
- LowNo special conditions are needed; the attack works reliably.
- 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:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: gtp: fix use-after-free and null-ptr-deref in gtp_newlink() The gtp_link_ops operations structure for the subsystem must be registered after registering the gtp_net_ops pernet operations structure. Syzkaller hit 'general protection fault in gtp_genl_dump_pdp' bug: [ 1010.702740] gtp: GTP module unloaded [ 1010.715877] general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] SMP KASAN NOPTI [ 1010.715888] KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] [ 1010.715895] CPU: 1 PID: 128616 Comm: a.out Not tainted 6.8.0-rc6-std-def-alt1 #1 [ 1010.715899] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.0-alt1 04/01/2014 [ 1010.715908] RIP: 0010:gtp_newlink+0x4d7/0x9c0 [gtp] [ 1010.715915] Code: 80 3c 02 00 0f 85 41 04 00 00 48 8b bb d8 05 00 00 e8 ed f6 ff ff 48 89 c2 48 89 c5 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 4f 04 00 00 4c 89 e2 4c 8b 6d 00 48 b8 00 00 00 [ 1010.715920] RSP: 0018:ffff888020fbf180 EFLAGS: 00010203 [ 1010.715929] RAX: dffffc0000000000 RBX: ffff88800399c000 RCX: 0000000000000000 [ 1010.715933] RDX: 0000000000000001 RSI: ffffffff84805280 RDI: 0000000000000282 [ 1010.715938] RBP: 000000000000000d R08: 0000000000000001 R09: 0000000000000000 [ 1010.715942] R10: 0000000000000001 R11: 0000000000000001 R12: ffff88800399cc80 [ 1010.715947] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000400 [ 1010.715953] FS: 00007fd1509ab5c0(0000) GS:ffff88805b300000(0000) knlGS:0000000000000000 [ 1010.715958] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1010.715962] CR2: 0000000000000000 CR3: 000000001c07a000 CR4: 0000000000750ee0 [ 1010.715968] PKRU: 55555554 [ 1010.715972] Call Trace: [ 1010.715985] ? __die_body.cold+0x1a/0x1f [ 1010.715995] ? die_addr+0x43/0x70 [ 1010.716002] ? exc_general_protection+0x199/0x2f0 [ 1010.716016] ? asm_exc_general_protection+0x1e/0x30 [ 1010.716026] ? gtp_newlink+0x4d7/0x9c0 [gtp] [ 1010.716034] ? gtp_net_exit+0x150/0x150 [gtp] [ 1010.716042] __rtnl_newlink+0x1063/0x1700 [ 1010.716051] ? rtnl_setlink+0x3c0/0x3c0 [ 1010.716063] ? is_bpf_text_address+0xc0/0x1f0 [ 1010.716070] ? kernel_text_address.part.0+0xbb/0xd0 [ 1010.716076] ? __kernel_text_address+0x56/0xa0 [ 1010.716084] ? unwind_get_return_address+0x5a/0xa0 [ 1010.716091] ? create_prof_cpu_mask+0x30/0x30 [ 1010.716098] ? arch_stack_walk+0x9e/0xf0 [ 1010.716106] ? stack_trace_save+0x91/0xd0 [ 1010.716113] ? stack_trace_consume_entry+0x170/0x170 [ 1010.716121] ? __lock_acquire+0x15c5/0x5380 [ 1010.716139] ? mark_held_locks+0x9e/0xe0 [ 1010.716148] ? kmem_cache_alloc_trace+0x35f/0x3c0 [ 1010.716155] ? __rtnl_newlink+0x1700/0x1700 [ 1010.716160] rtnl_newlink+0x69/0xa0 [ 1010.716166] rtnetlink_rcv_msg+0x43b/0xc50 [ 1010.716172] ? rtnl_fdb_dump+0x9f0/0x9f0 [ 1010.716179] ? lock_acquire+0x1fe/0x560 [ 1010.716188] ? netlink_deliver_tap+0x12f/0xd50 [ 1010.716196] netlink_rcv_skb+0x14d/0x440 [ 1010.716202] ? rtnl_fdb_dump+0x9f0/0x9f0 [ 1010.716208] ? netlink_ack+0xab0/0xab0 [ 1010.716213] ? netlink_deliver_tap+0x202/0xd50 [ 1010.716220] ? netlink_deliver_tap+0x218/0xd50 [ 1010.716226] ? __virt_addr_valid+0x30b/0x590 [ 1010.716233] netlink_unicast+0x54b/0x800 [ 1010.716240] ? netlink_attachskb+0x870/0x870 [ 1010.716248] ? __check_object_size+0x2de/0x3b0 [ 1010.716254] netlink_sendmsg+0x938/0xe40 [ 1010.716261] ? netlink_unicast+0x800/0x800 [ 1010.716269] ? __import_iovec+0x292/0x510 [ 1010.716276] ? netlink_unicast+0x800/0x800 [ 1010.716284] __sock_sendmsg+0x159/0x190 [ 1010.716290] ____sys_sendmsg+0x712/0x880 [ 1010.716297] ? sock_write_iter+0x3d0/0x3d0 [ 1010.716304] ? __ia32_sys_recvmmsg+0x270/0x270 [ 1010.716309] ? lock_acquire+0x1fe/0x560 [ 1010.716315] ? drain_array_locked+0x90/0x90 [ 1010.716324] ___sys_sendmsg+0xf8/0x170 [ 1010.716331] ? sendmsg_copy_msghdr+0x170/0x170 [ 1010.716337] ? lockdep_init_map ---truncated---
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
- git.kernel.org/stable/c/01129059d5141d62fae692f7a336ae3bc712d3eb
- git.kernel.org/stable/c/5366969a19a8a0d2ffb3d27ef6e8905e5e4216f8
- git.kernel.org/stable/c/616d82c3cfa2a2146dd7e3ae47bda7e877ee549e
- git.kernel.org/stable/c/9376d059a705c5dfaac566c2d09891242013ae16
- git.kernel.org/stable/c/93dd420bc41531c9a31498b9538ca83ba6ec191e
- git.kernel.org/stable/c/abd32d7f5c0294c1b2454c5a3b13b18446bac627
- git.kernel.org/stable/c/e668b92a3a01429923fd5ca13e99642aab47de69
- git.kernel.org/stable/c/ec92aa2cab6f0048f10d6aa4f025c5885cb1a1b6
- lists.debian.org/debian-lts-announce/2024/06/msg00017.html
- lists.debian.org/debian-lts-announce/2024/06/msg00020.html
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