7.8

CVE-2021-47638: ubifs: rename_whiteout: Fix double free for whiteout_ui->data

Modified
AliasesUBUNTU-CVE-2021-47638DEBIAN-CVE-2021-47638
Published 26-02-2025Last modified 05-08-2026

Vulnerability summary

CVE-2021-47638 is a high (CVSS 7.8) Double Free vulnerability in linux. EPSS estimates a 0.26% chance of exploitation in the next 30 days, higher than 17.8% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 7.8, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
7.8/10
010
High · v3.1 (CVE.org)
EPSS score
0.26%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 4 · Related 4
SUSE-SU-2025:1027-1SUSE-SU-2025:1176-1SUSE-SU-2025:1183-1SUSE-SU-2025:1241-1

Timeline

  1. 26-02-2025
    PublishedVulnerability first disclosed.
  2. 05-08-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: ubifs: rename_whiteout: Fix double free for whiteout_ui->data 'whiteout_ui->data' will be freed twice if space budget fail for rename whiteout operation as following process: rename_whiteout dev = kmalloc whiteout_ui->data = dev kfree(whiteout_ui->data) // Free first time iput(whiteout) ubifs_free_inode kfree(ui->data) // Double free! KASAN reports: ================================================================== BUG: KASAN: double-free or invalid-free in ubifs_free_inode+0x4f/0x70 Call Trace: kfree+0x117/0x490 ubifs_free_inode+0x4f/0x70 [ubifs] i_callback+0x30/0x60 rcu_do_batch+0x366/0xac0 __do_softirq+0x133/0x57f Allocated by task 1506: kmem_cache_alloc_trace+0x3c2/0x7a0 do_rename+0x9b7/0x1150 [ubifs] ubifs_rename+0x106/0x1f0 [ubifs] do_syscall_64+0x35/0x80 Freed by task 1506: kfree+0x117/0x490 do_rename.cold+0x53/0x8a [ubifs] ubifs_rename+0x106/0x1f0 [ubifs] do_syscall_64+0x35/0x80 The buggy address belongs to the object at ffff88810238bed8 which belongs to the cache kmalloc-8 of size 8 ================================================================== Let ubifs_free_inode() free 'whiteout_ui->data'. BTW, delete unused assignment 'whiteout_ui->data_len = 0', process 'ubifs_evict_inode() -> ubifs_jnl_delete_inode() -> ubifs_jnl_write_inode()' doesn't need it (because 'inc_nlink(whiteout)' won't be excuted by 'goto out_release', and the nlink of whiteout inode is 0).

CVSS metrics

5 scores · 4 sources · 2 versions

EPSS trend

Probability

0.26%

Chance of exploitation in the next 30 days

Percentile

18%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.26% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu105 products
  • linux< 4.15.0-189.200 | < 5.4.0-117.132 | < 5.15.0-37.39
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws< 4.15.0-1137.148 | < 5.4.0-1078.84 | < 5.15.0-1011.14
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ 9e0a1fff8db56eaaebb74b4a3ef65f86811c4798, < 8b3c7be16f3f4dfd6e15ac651484e59d3fa36274 | ≥ 9e0a1fff8db56eaaebb74b4a3ef65f86811c4798, < 2b3236ecf96db7af5836e1366ce39ace8ce832fa | ≥ 9e0a1fff8db56eaaebb74b4a3ef65f86811c4798, < 14276d38c89a170363e90b6ac0a53c3cf61b87fc | ≥ 9e0a1fff8db56eaaebb74b4a3ef65f86811c4798, < a90e2dbe66d2647ff95a0442ad2e86482d977fd8 | ≥ 9e0a1fff8db56eaaebb74b4a3ef65f86811c4798, < 2ad07009c459e56ebdcc089d850d664660fdb742 | ≥ 9e0a1fff8db56eaaebb74b4a3ef65f86811c4798, < b9a937f096e608b3368c1abc920d4d640ba2c94f | ≥ 9e0a1fff8db56eaaebb74b4a3ef65f86811c4798, < 6d7a158a7363c1f6604aa47ae1a280a5c65123dd | ≥ 9e0a1fff8db56eaaebb74b4a3ef65f86811c4798, < 40a8f0d5e7b3999f096570edab71c345da812e3e | 4.9
  • linux_kernel≥ 4.9, < 4.14.276 | ≥ 4.15, < 4.19.238 | ≥ 4.20, < 5.4.189 | ≥ 5.5, < 5.10.110 | ≥ 5.11, < 5.15.33 | ≥ 5.16, < 5.16.19 | ≥ 5.17, < 5.17.2
Debian1 product
  • linux< 5.17.3-1

3 vendors · 108 products

References

12 links
Show all 12 references