7.8

CVE-2021-47082: linux Double Free

CVSS: 7.8v3.1HighModified
AliasesUBUNTU-CVE-2021-47082DEBIAN-CVE-2021-47082
Published 04-03-2024Last modified 05-08-2026
Open JSON

Vulnerability summary

CVE-2021-47082 is a high (CVSS 7.8) Double Free vulnerability in linux. EPSS estimates a 0.25% chance of exploitation in the next 30 days, higher than 15.6% of scored vulnerabilities.

Overall risk
31/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.8/10
010
High · v3.1 (CVE.org)
EPSS score
0.25%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 10 · Related 10
SUSE-SU-2024:1320-1SUSE-SU-2024:1321-1SUSE-SU-2024:1454-1SUSE-SU-2024:1465-1SUSE-SU-2024:1466-1SUSE-SU-2024:1480-1

Timeline

  1. 04-03-2024
    PublishedVulnerability first disclosed.
  2. 05-08-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: tun: avoid double free in tun_free_netdev Avoid double free in tun_free_netdev() by moving the dev->tstats and tun->security allocs to a new ndo_init routine (tun_net_init()) that will be called by register_netdevice(). ndo_init is paired with the desctructor (tun_free_netdev()), so if there's an error in register_netdevice() the destructor will handle the frees. BUG: KASAN: double-free or invalid-free in selinux_tun_dev_free_security+0x1a/0x20 security/selinux/hooks.c:5605 CPU: 0 PID: 25750 Comm: syz-executor416 Not tainted 5.16.0-rc2-syzk #1 Hardware name: Red Hat KVM, BIOS Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x89/0xb5 lib/dump_stack.c:106 print_address_description.constprop.9+0x28/0x160 mm/kasan/report.c:247 kasan_report_invalid_free+0x55/0x80 mm/kasan/report.c:372 ____kasan_slab_free mm/kasan/common.c:346 [inline] __kasan_slab_free+0x107/0x120 mm/kasan/common.c:374 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:1723 [inline] slab_free_freelist_hook mm/slub.c:1749 [inline] slab_free mm/slub.c:3513 [inline] kfree+0xac/0x2d0 mm/slub.c:4561 selinux_tun_dev_free_security+0x1a/0x20 security/selinux/hooks.c:5605 security_tun_dev_free_security+0x4f/0x90 security/security.c:2342 tun_free_netdev+0xe6/0x150 drivers/net/tun.c:2215 netdev_run_todo+0x4df/0x840 net/core/dev.c:10627 rtnl_unlock+0x13/0x20 net/core/rtnetlink.c:112 __tun_chr_ioctl+0x80c/0x2870 drivers/net/tun.c:3302 tun_chr_ioctl+0x2f/0x40 drivers/net/tun.c:3311 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x19d/0x220 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3a/0x80 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.25%

Chance of exploitation in the next 30 days

Percentile

16%

Versus all other CVEs

30-day change

0.00 pp

From 0.25% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.25%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Ubuntu89 products
  • linux< 4.15.0-232.244 | < 5.4.0-156.173
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws< 4.15.0-1176.189 | < 5.4.0-1107.115
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ 662ca437e714caaab855b12415d6ffd815985bc0, < 8eb43d635950e27c29f1e9e49a23b31637f37757 | ≥ 662ca437e714caaab855b12415d6ffd815985bc0, < 0c0e566f0387490d16f166808c72e9c772027681 | ≥ 662ca437e714caaab855b12415d6ffd815985bc0, < a01a4e9f5dc93335c716fa4023b1901956e8c904 | ≥ 662ca437e714caaab855b12415d6ffd815985bc0, < 3cb5ae77799e8ed6ec3fec0b6b4cd07f01650cc5 | ≥ 662ca437e714caaab855b12415d6ffd815985bc0, < 158b515f703e75e7d68289bf4d98c664e1d632df | a81a02460bdf054ca0c60c5aed29941f7134092d | 6fc265f7a86d81e052508d03da555188f5882c3e | ≥ 3.10.16, < 3.11 | ≥ 3.11.5, < 3.12 | 3.12
  • linux_kernel< 4.19.280 | ≥ 4.20, < 5.4.240 | ≥ 5.5, < 5.10.136 | ≥ 5.11, < 5.15.12 | 5.16:rc1 | 5.16:rc2 | 5.16:rc3 | 5.16:rc4 | 5.16:rc5 | 5.16:rc6
Debian1 product
  • linux< 5.15.15-1

3 vendors · 92 products

References

11 links
Show all 11 references