CVE-2021-46972: ovl: fix leaked dentry
Noroxi assessment
Priority: Monitor (action score 22/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.24% (FIRST EPSS).
- Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
- Fixed version: Linux Linux 71d58457a8afc650da5d3292a7f7029317654d95, cf3e3330bc5719fa9d658e3e2f596bde89344a94, d587cfaef72b1b6f4b2774827123bce91f497cc8.
- Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Low priority for now. Upgrade to Linux Linux 71d58457a8afc650da5d3292a7f7029317654d95, cf3e3330bc5719fa9d658e3e2f596bde89344a94, d587cfaef72b1b6f4b2774827123bce91f497cc8 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
In the Linux kernel, the following vulnerability has been resolved: ovl: fix leaked dentry Since commit 6815f479ca90 ("ovl: use only uppermetacopy state in ovl_lookup()"), overlayfs doesn't put temporary dentry when there is a metacopy error, which leads to dentry leaks when shutting down the related superblock: overlayfs: refusing to follow metacopy origin for (/file0) ... BUG: Dentry (____ptrval____){i=3f33,n=file3} still in use (1) [unmount of overlay overlay] ... WARNING: CPU: 1 PID: 432 at umount_check.cold+0x107/0x14d CPU: 1 PID: 432 Comm: unmount-overlay Not tainted 5.12.0-rc5 #1 ... RIP: 0010:umount_check.cold+0x107/0x14d ... Call Trace: d_walk+0x28c/0x950 ? dentry_lru_isolate+0x2b0/0x2b0 ? __kasan_slab_free+0x12/0x20 do_one_tree+0x33/0x60 shrink_dcache_for_umount+0x78/0x1d0 generic_shutdown_super+0x70/0x440 kill_anon_super+0x3e/0x70 deactivate_locked_super+0xc4/0x160 deactivate_super+0xfa/0x140 cleanup_mnt+0x22e/0x370 __cleanup_mnt+0x1a/0x30 task_work_run+0x139/0x210 do_exit+0xb0c/0x2820 ? __kasan_check_read+0x1d/0x30 ? find_held_lock+0x35/0x160 ? lock_release+0x1b6/0x660 ? mm_update_next_owner+0xa20/0xa20 ? reacquire_held_locks+0x3f0/0x3f0 ? __sanitizer_cov_trace_const_cmp4+0x22/0x30 do_group_exit+0x135/0x380 __do_sys_exit_group.isra.0+0x20/0x20 __x64_sys_exit_group+0x3c/0x50 do_syscall_64+0x45/0x70 entry_SYSCALL_64_after_hwframe+0x44/0xae ... VFS: Busy inodes after unmount of overlay. Self-destruct in 5 seconds. Have a nice day... This fix has been tested with a syzkaller reproducer.
- Published
- Feb 27, 2024
- Updated
- Jun 17, 2026
- EPSS
- 0.2% · 16th percentile
- CWE
- CWE-401
Report tools
Action score
22
Monitor
Low priority for now.
- CVSS
- 22 / 40 · 5.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.2%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
Is your version affected? Check itNoroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| linux | linux kernel | cpe:2.3:o:linux:linux_kernel |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- linux linux kernel5.8 and later · before 5.10.35
- linux linux kernel5.11 and later · before 5.11.19
- linux linux kernel5.12 and later · before 5.12.2
Versions reported by the vendor
Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.
Linux Linux
- 5.8affected
- 6815f479ca90ee7fd2e28b2a420f796b974155fe and later · before 71d58457a8afc650da5d3292a7f7029317654d95affected · git
- 6815f479ca90ee7fd2e28b2a420f796b974155fe and later · before cf3e3330bc5719fa9d658e3e2f596bde89344a94affected · git
- 6815f479ca90ee7fd2e28b2a420f796b974155fe and later · before d587cfaef72b1b6f4b2774827123bce91f497cc8affected · git
- 6815f479ca90ee7fd2e28b2a420f796b974155fe and later · before eaab1d45cdb4bb0c846bd23c3d666d5b90af7b41affected · git
- before 5.8not affected · semver
- 5.10.35 and later · up to and including 5.10.*not affected · semver
- 5.11.19 and later · up to and including 5.11.*not affected · semver
- 5.12.2 and later · up to and including 5.12.*not affected · semver
- 5.13 and laternot affected · original_commit_for_fix
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:8 | bpftool | before 4.18.0-553.8.1.el8_10 | 4.18.0-553.8.1.el8_10 |
| AlmaLinux:8 | kernel | before 4.18.0-553.8.1.el8_10 | 4.18.0-553.8.1.el8_10 |
| AlmaLinux:8 | kernel-abi-stablelists | before 4.18.0-553.8.1.el8_10 | 4.18.0-553.8.1.el8_10 |
| AlmaLinux:8 | kernel-core | before 4.18.0-553.8.1.el8_10 | 4.18.0-553.8.1.el8_10 |
| AlmaLinux:8 | kernel-cross-headers | before 4.18.0-553.8.1.el8_10 | 4.18.0-553.8.1.el8_10 |
| AlmaLinux:8 | kernel-debug | before 4.18.0-553.8.1.el8_10 | 4.18.0-553.8.1.el8_10 |
| AlmaLinux:8 | kernel-debug-core | before 4.18.0-553.8.1.el8_10 | 4.18.0-553.8.1.el8_10 |
| AlmaLinux:8 | kernel-debug-devel | before 4.18.0-553.8.1.el8_10 | 4.18.0-553.8.1.el8_10 |
| AlmaLinux:8 | kernel-debug-modules | before 4.18.0-553.8.1.el8_10 | 4.18.0-553.8.1.el8_10 |
| AlmaLinux:8 | kernel-debug-modules-extra | before 4.18.0-553.8.1.el8_10 | 4.18.0-553.8.1.el8_10 |
| AlmaLinux:8 | kernel-devel | before 4.18.0-553.8.1.el8_10 | 4.18.0-553.8.1.el8_10 |
| AlmaLinux:8 | kernel-doc | before 4.18.0-553.8.1.el8_10 | 4.18.0-553.8.1.el8_10 |
| AlmaLinux:8 | kernel-headers | before 4.18.0-553.8.1.el8_10 | 4.18.0-553.8.1.el8_10 |
| AlmaLinux:8 | kernel-modules | before 4.18.0-553.8.1.el8_10 | 4.18.0-553.8.1.el8_10 |
| AlmaLinux:8 | kernel-modules-extra | before 4.18.0-553.8.1.el8_10 | 4.18.0-553.8.1.el8_10 |
| AlmaLinux:8 | kernel-rt | before 4.18.0-553.8.1.rt7.349.el8_10 | 4.18.0-553.8.1.rt7.349.el8_10 |
| AlmaLinux:8 | kernel-rt-core | before 4.18.0-553.8.1.rt7.349.el8_10 | 4.18.0-553.8.1.rt7.349.el8_10 |
| AlmaLinux:8 | kernel-rt-debug | before 4.18.0-553.8.1.rt7.349.el8_10 | 4.18.0-553.8.1.rt7.349.el8_10 |
| AlmaLinux:8 | kernel-rt-debug-core | before 4.18.0-553.8.1.rt7.349.el8_10 | 4.18.0-553.8.1.rt7.349.el8_10 |
| AlmaLinux:8 | kernel-rt-debug-devel | before 4.18.0-553.8.1.rt7.349.el8_10 | 4.18.0-553.8.1.rt7.349.el8_10 |
| AlmaLinux:8 | kernel-rt-debug-kvm | before 4.18.0-553.8.1.rt7.349.el8_10 | 4.18.0-553.8.1.rt7.349.el8_10 |
| AlmaLinux:8 | kernel-rt-debug-modules | before 4.18.0-553.8.1.rt7.349.el8_10 | 4.18.0-553.8.1.rt7.349.el8_10 |
| AlmaLinux:8 | kernel-rt-debug-modules-extra | before 4.18.0-553.8.1.rt7.349.el8_10 | 4.18.0-553.8.1.rt7.349.el8_10 |
| AlmaLinux:8 | kernel-rt-devel | before 4.18.0-553.8.1.rt7.349.el8_10 | 4.18.0-553.8.1.rt7.349.el8_10 |
+65
Same product
linux: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV90Now
- CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe…KEV89Now
- CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV85Now
Published before and after this one in the same product
- ← EarlierCVE-2021-46970Feb 27, 2024 · bus: mhi: pci_generic: Remove WQ_MEM_RECLAIM flag from state workqueue22Monitor
- ← EarlierCVE-2021-46971Feb 27, 2024 · perf/core: Fix unconditional security_locked_down() call13Monitor
- Later →CVE-2021-46973Feb 27, 2024 · net: qrtr: Avoid potential use after free in MHI send31Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Linux Linux | 71d58457a8afc650da5d3292a7f7029317654d95 | Vendor (CNA) |
| Linux Linux | cf3e3330bc5719fa9d658e3e2f596bde89344a94 | Vendor (CNA) |
| Linux Linux | d587cfaef72b1b6f4b2774827123bce91f497cc8 | Vendor (CNA) |
| Linux Linux | eaab1d45cdb4bb0c846bd23c3d666d5b90af7b41 | Vendor (CNA) |
| almalinux:bpftool | 4.18.0-553.8.1.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:kernel | 4.18.0-553.8.1.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:kernel-abi-stablelists | 4.18.0-553.8.1.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:kernel-core | 4.18.0-553.8.1.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:kernel-cross-headers | 4.18.0-553.8.1.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:kernel-debug | 4.18.0-553.8.1.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:kernel-debug-core | 4.18.0-553.8.1.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:kernel-debug-devel | 4.18.0-553.8.1.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:kernel-debug-modules | 4.18.0-553.8.1.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:kernel-debug-modules-extra | 4.18.0-553.8.1.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:kernel-devel | 4.18.0-553.8.1.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:kernel-doc | 4.18.0-553.8.1.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| debian:linux | 5.10.38-1 · Debian:12 | Package registry (OSV) |
| red hat:bpftool | 0:4.18.0-553.8.1.el8_10 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:bpftool-debuginfo | 0:4.18.0-553.8.1.el8_10 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:kernel | 0:4.18.0-553.8.1.el8_10 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:kernel-abi-stablelists | 0:4.18.0-553.8.1.el8_10 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:kernel-core | 0:4.18.0-553.8.1.el8_10 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:kernel-debug | 0:4.18.0-553.8.1.el8_10 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:kernel-debug-core | 0:4.18.0-553.8.1.el8_10 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:kernel-debug-debuginfo | 0:4.18.0-553.8.1.el8_10 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:kernel-debug-devel | 0:4.18.0-553.8.1.el8_10 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:kernel-debug-modules | 0:4.18.0-553.8.1.el8_10 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:kernel-debug-modules-extra | 0:4.18.0-553.8.1.el8_10 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:kernel-debuginfo | 0:4.18.0-553.8.1.el8_10 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| rocky linux:kernel | 0:4.18.0-553.8.1.el8_10 · Rocky Linux:8 | Package registry (OSV) |
+1
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
No history yet (it accumulates with the daily EPSS job).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
National notice (Türkiye Cybersecurity Directorate / USOM)
Official security notices citing this record; remediation advice is on the agency's page.
- TR-24-0138 · Feb 28, 2024(Linux Kernel Güncellemesi)
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-401 · Missing Release of Memory after Effective LifetimeCVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (3 more)Show less
Vendor advisories and official records. Exploit/PoC links are deliberately left out.