CVE-2021-46955

Advisory lineage Upstream: 0 Downstream: 64
Analyzed
Published: 27 Feb 2024, 18:46
Last modified:23 May 2026, 15:18

Vulnerability Summary

Overall Risk (default)
medium
28/100
CVSS Score
7.1 HIGH
v3.1 (nvd)
EPSS Score
0.01% LOW
0% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

27 Feb 2024, 18:46
Published
Vulnerability first disclosed
23 May 2026, 15:18
Last Modified
Vulnerability information updated

Description

In the Linux kernel, the following vulnerability has been resolved: openvswitch: fix stack OOB read while fragmenting IPv4 packets running openvswitch on kernels built with KASAN, it's possible to see the following splat while testing fragmentation of IPv4 packets: BUG: KASAN: stack-out-of-bounds in ip_do_fragment+0x1b03/0x1f60 Read of size 1 at addr ffff888112fc713c by task handler2/1367 CPU: 0 PID: 1367 Comm: handler2 Not tainted 5.12.0-rc6+ #418 Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014 Call Trace: dump_stack+0x92/0xc1 print_address_description.constprop.7+0x1a/0x150 kasan_report.cold.13+0x7f/0x111 ip_do_fragment+0x1b03/0x1f60 ovs_fragment+0x5bf/0x840 [openvswitch] do_execute_actions+0x1bd5/0x2400 [openvswitch] ovs_execute_actions+0xc8/0x3d0 [openvswitch] ovs_packet_cmd_execute+0xa39/0x1150 [openvswitch] genl_family_rcv_msg_doit.isra.15+0x227/0x2d0 genl_rcv_msg+0x287/0x490 netlink_rcv_skb+0x120/0x380 genl_rcv+0x24/0x40 netlink_unicast+0x439/0x630 netlink_sendmsg+0x719/0xbf0 sock_sendmsg+0xe2/0x110 ____sys_sendmsg+0x5ba/0x890 ___sys_sendmsg+0xe9/0x160 __sys_sendmsg+0xd3/0x170 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f957079db07 Code: c3 66 90 41 54 41 89 d4 55 48 89 f5 53 89 fb 48 83 ec 10 e8 eb ec ff ff 44 89 e2 48 89 ee 89 df 41 89 c0 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 48 89 44 24 08 e8 24 ed ff ff 48 RSP: 002b:00007f956ce35a50 EFLAGS: 00000293 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000019 RCX: 00007f957079db07 RDX: 0000000000000000 RSI: 00007f956ce35ae0 RDI: 0000000000000019 RBP: 00007f956ce35ae0 R08: 0000000000000000 R09: 00007f9558006730 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 00007f956ce37308 R14: 00007f956ce35f80 R15: 00007f956ce35ae0 The buggy address belongs to the page: page:00000000af2a1d93 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x112fc7 flags: 0x17ffffc0000000() raw: 0017ffffc0000000 0000000000000000 dead000000000122 0000000000000000 raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected addr ffff888112fc713c is located in stack of task handler2/1367 at offset 180 in frame: ovs_fragment+0x0/0x840 [openvswitch] this frame has 2 objects: [32, 144) 'ovs_dst' [192, 424) 'ovs_rt' Memory state around the buggy address: ffff888112fc7000: f3 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888112fc7080: 00 f1 f1 f1 f1 00 00 00 00 00 00 00 00 00 00 00 >ffff888112fc7100: 00 00 00 f2 f2 f2 f2 f2 f2 00 00 00 00 00 00 00 ^ ffff888112fc7180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888112fc7200: 00 00 00 00 00 00 f2 f2 f2 00 00 00 00 00 00 00 for IPv4 packets, ovs_fragment() uses a temporary struct dst_entry. Then, in the following call graph: ip_do_fragment() ip_skb_dst_mtu() ip_dst_mtu_maybe_forward() ip_mtu_locked() the pointer to struct dst_entry is used as pointer to struct rtable: this turns the access to struct members like rt_mtu_locked into an OOB read in the stack. Fix this changing the temporary variable used for IPv4 packets in ovs_fragment(), similarly to what is done for IPv6 few lines below.

CVSS Metrics

  • v3.1•HIGH•Score: 7.1CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

EPSS Trends

Current EPSS score: 0.01%• Percentile: 1%

Techniques & Countermeasures

  • CWE-125•Out-of-bounds Read

    The product reads data past the end, or before the beginning, of the intended buffer.

Affected Systems

  • linux•linux

    ≥ 119bbaa6795a4f4aed46994cc7d9ab01989c87e3, < b1d7280f9ba1bfdbc3af5bdb82e51f014854f26f | ≥ d543907a4730400f5c5b684c57cb5bbbfd6136ab, < 23e17ec1a5eb53fe39cc34fa5592686d5acd0dac | ≥ 8387fbac8e18e26a60559adc63e0b7067303b0a4, < 5a52fa8ad45b5a593ed416adf326538638454ff1 | ≥ d52e5a7e7ca49457dd31fc8b42fb7c0d58a31221, < df9e900de24637be41879e2c50afb713ec4e8b2e | ≥ d52e5a7e7ca49457dd31fc8b42fb7c0d58a31221, < 490ad0a2390442d0a7b8c00972a83dbb09cab142 | ≥ d52e5a7e7ca49457dd31fc8b42fb7c0d58a31221, < a1478374b0bda89b4277a8afd39208271faad4be | ≥ d52e5a7e7ca49457dd31fc8b42fb7c0d58a31221, < d841d3cf5297fde4ce6a41ff35451d0e82917f3e | ≥ d52e5a7e7ca49457dd31fc8b42fb7c0d58a31221, < b3502b04e84ac5349be95fc033c17bd701d2787a | ≥ d52e5a7e7ca49457dd31fc8b42fb7c0d58a31221, < 7c0ea5930c1c211931819d83cfb157bff1539a4c | df9ece1148e2ec242871623dedb004f7a1387125 | ≥ 4.4.134, < 4.4.269 | ≥ 4.9.104, < 4.9.269 | ≥ 4.14.45, < 4.14.233 | ≥ 3.16.57, < 3.17 | 4.16

  • linux•linux_kernel

    ≥ 4.4.134, < 4.4.269 | ≥ 4.9.104, < 4.9.269 | ≥ 4.14.45, < 4.14.233 | ≥ 4.16, < 4.19.191 | ≥ 4.20, < 5.4.118 | ≥ 5.5, < 5.10.36 | ≥ 5.11, < 5.11.20 | ≥ 5.12, < 5.12.3

References (9)