Linux Kernel up to 6.0.8 net tun_get_user memory leak

Summaryinfo

A vulnerability marked as critical has been reported in Linux Kernel up to 4.19.266/5.4.224/5.10.154/5.15.78/6.0.8. This affects the function tun_get_user of the component net. This manipulation causes memory leak. This vulnerability is registered as CVE-2022-49871. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 4.19.266/5.4.224/5.10.154/5.15.78/6.0.8. Affected by this vulnerability is the function tun_get_user of the component net. The manipulation with an unknown input leads to a memory leak vulnerability. The CWE definition for the vulnerability is CWE-401. The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory. As an impact it is known to affect availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: net: tun: Fix memory leaks of napi_get_frags kmemleak reports after running test_progs: unreferenced object 0xffff8881b1672dc0 (size 232): comm "test_progs", pid 394388, jiffies 4354712116 (age 841.975s) hex dump (first 32 bytes): e0 84 d7 a8 81 88 ff ff 80 2c 67 b1 81 88 ff ff .........,g..... 00 40 c5 9b 81 88 ff ff 00 00 00 00 00 00 00 00 .@.............. backtrace: [] napi_skb_cache_get+0xd4/0x150 [] __napi_build_skb+0x15/0x50 [] __napi_alloc_skb+0x26e/0x540 [] napi_get_frags+0x59/0x140 [] tun_get_user+0x183d/0x3bb0 [tun] [] tun_chr_write_iter+0xc0/0x1b1 [tun] [] do_iter_readv_writev+0x19f/0x320 [] do_iter_write+0x135/0x630 [] vfs_writev+0x12e/0x440 [] do_writev+0x104/0x280 [] do_syscall_64+0x3b/0x90 [] entry_SYSCALL_64_after_hwframe+0x63/0xcd The issue occurs in the following scenarios: tun_get_user() napi_gro_frags() napi_frags_finish() case GRO_NORMAL: gro_normal_one() list_add_tail(&skb->list, &napi->rx_list); rx_count < READ_ONCE(gro_normal_batch), rx_list is not empty <-- not ask to complete the gro work, will cause memory leaks in <-- following tun_napi_del() ... tun_napi_del() netif_napi_del() __netif_napi_del() rx_list is not empty, which caused memory leaks To fix, add napi_complete() after napi_gro_frags().

The advisory is shared at git.kernel.org. This vulnerability is known as CVE-2022-49871 since 05/01/2025. The exploitation appears to be difficult. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 240793 (SUSE SLES12 Security Update : kernel (SUSE-SU-2025:01983-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 4.19.267, 5.4.225, 5.10.155, 5.15.79 or 6.0.9 eliminates this vulnerability. Applying the patch 223ef6a94e52331a6a7ef31e59921e0e82d2d40a/a4f73f6adc53fd7a3f9771cbc89a03ef39b0b755/3401f964028ac941425b9b2c8ff8a022539ef44a/d7569302a7a52a9305d2fb054df908ff985553bb/8b12a020b20a78f62bedc50f26db3bf4fadf8cb9/1118b2049d77ca0b505775fc1a8d1909cf19a7ec is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (240793). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 4.19.266
• 5.4.224
• 5.10.154
• 5.15.0
• 5.15.1
• 5.15.2
• 5.15.3
• 5.15.4
• 5.15.5
• 5.15.6
• 5.15.7
• 5.15.8
• 5.15.9
• 5.15.10
• 5.15.11
• 5.15.12
• 5.15.13
• 5.15.14
• 5.15.15
• 5.15.16
• 5.15.17
• 5.15.18
• 5.15.19
• 5.15.20
• 5.15.21
• 5.15.22
• 5.15.23
• 5.15.24
• 5.15.25
• 5.15.26
• 5.15.27
• 5.15.28
• 5.15.29
• 5.15.30
• 5.15.31
• 5.15.32
• 5.15.33
• 5.15.34
• 5.15.35
• 5.15.36
• 5.15.37
• 5.15.38
• 5.15.39
• 5.15.40
• 5.15.41
• 5.15.42
• 5.15.43
• 5.15.44
• 5.15.45
• 5.15.46
• 5.15.47
• 5.15.48
• 5.15.49
• 5.15.50
• 5.15.51
• 5.15.52
• 5.15.53
• 5.15.54
• 5.15.55
• 5.15.56
• 5.15.57
• 5.15.58
• 5.15.59
• 5.15.60
• 5.15.61
• 5.15.62
• 5.15.63
• 5.15.64
• 5.15.65
• 5.15.66
• 5.15.67
• 5.15.68
• 5.15.69
• 5.15.70
• 5.15.71
• 5.15.72
• 5.15.73
• 5.15.74
• 5.15.75
• 5.15.76
• 5.15.77
• 5.15.78
• 6.0.0
• 6.0.1
• 6.0.2
• 6.0.3
• 6.0.4
• 6.0.5
• 6.0.6
• 6.0.7
• 6.0.8

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

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