CVE-2021-47189: btrfs: fix memory ordering between normal and ordered work functions
Noroxi assessment
Priority: Monitor (action score 31/100)
- 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: 0.67% (FIRST EPSS); higher than 52.2% of all records.
- 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 45da9c1767ac31857df572f0a909fbe88fd5a7e9, 47e6f9f69153247109042010f3a77579e9dc61ff, 637d652d351fd4f263ef302dc52f3971d314e500.
- Mentioned 2 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Low priority for now. Upgrade to Linux Linux 45da9c1767ac31857df572f0a909fbe88fd5a7e9, 47e6f9f69153247109042010f3a77579e9dc61ff, 637d652d351fd4f263ef302dc52f3971d314e500 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: btrfs: fix memory ordering between normal and ordered work functions Ordered work functions aren't guaranteed to be handled by the same thread which executed the normal work functions. The only way execution between normal/ordered functions is synchronized is via the WORK_DONE_BIT, unfortunately the used bitops don't guarantee any ordering whatsoever. This manifested as seemingly inexplicable crashes on ARM64, where async_chunk::inode is seen as non-null in async_cow_submit which causes submit_compressed_extents to be called and crash occurs because async_chunk::inode suddenly became NULL. The call trace was similar to: pc : submit_compressed_extents+0x38/0x3d0 lr : async_cow_submit+0x50/0xd0 sp : ffff800015d4bc20 <registers omitted for brevity> Call trace: submit_compressed_extents+0x38/0x3d0 async_cow_submit+0x50/0xd0 run_ordered_work+0xc8/0x280 btrfs_work_helper+0x98/0x250 process_one_work+0x1f0/0x4ac worker_thread+0x188/0x504 kthread+0x110/0x114 ret_from_fork+0x10/0x18 Fix this by adding respective barrier calls which ensure that all accesses preceding setting of WORK_DONE_BIT are strictly ordered before setting the flag. At the same time add a read barrier after reading of WORK_DONE_BIT in run_ordered_work which ensures all subsequent loads would be strictly ordered after reading the bit. This in turn ensures are all accesses before WORK_DONE_BIT are going to be strictly ordered before any access that can occur in ordered_func.
- Published
- Apr 10, 2024
- Updated
- Aug 5, 2026
- EPSS
- 0.6% · 52th percentile
- CWE
- —
Report tools
Action score
31
Monitor
Low priority for now.
- CVSS
- 31 / 40 · 7.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.6%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · Linux
- 7.8
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
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.
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Noroxi 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 kernel3.15 and later · before 4.4.293
- linux linux kernel4.5 and later · before 4.9.291
- linux linux kernel4.10 and later · before 4.14.256
- linux linux kernel4.15 and later · before 4.19.218
- linux linux kernel4.20 and later · before 5.4.162
- linux linux kernel5.5 and later · before 5.10.82
- linux linux kernel5.11 and later · before 5.15.5
- linux linux kernel5.16
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
- 3.15affected
- 08a9ff3264181986d1d692a4e6fce3669700c9f8 and later · before bd660a20fea3ec60a49709ef5360f145ec0fe779affected · git
- 08a9ff3264181986d1d692a4e6fce3669700c9f8 and later · before 637d652d351fd4f263ef302dc52f3971d314e500affected · git
- 08a9ff3264181986d1d692a4e6fce3669700c9f8 and later · before 804a9d239ae9cbe88e861a7cd62319cc6ec7b136affected · git
- 08a9ff3264181986d1d692a4e6fce3669700c9f8 and later · before ed058d735a70f4b063323f1a7bb33cda0f987513affected · git
- 08a9ff3264181986d1d692a4e6fce3669700c9f8 and later · before 670f6b3867c8f0f11e5097f353b164cecfec6179affected · git
- 08a9ff3264181986d1d692a4e6fce3669700c9f8 and later · before 6adbc07ebcaf8bead08b21687d49e0fc94400987affected · git
- 08a9ff3264181986d1d692a4e6fce3669700c9f8 and later · before 47e6f9f69153247109042010f3a77579e9dc61ffaffected · git
- 08a9ff3264181986d1d692a4e6fce3669700c9f8 and later · before 45da9c1767ac31857df572f0a909fbe88fd5a7e9affected · git
- before 3.15not affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | linux | before 5.15.5-1 | 5.15.5-1 |
| openSUSE:Leap 15.5 | dtb-aarch64 | before 5.14.21-150500.55.62.1 | 5.14.21-150500.55.62.1 |
| openSUSE:Leap 15.5 | kernel-64kb | before 5.14.21-150500.55.62.2 | 5.14.21-150500.55.62.2 |
| openSUSE:Leap 15.5 | kernel-debug | before 5.14.21-150500.55.62.2 | 5.14.21-150500.55.62.2 |
| openSUSE:Leap 15.5 | kernel-default | before 5.14.21-150500.55.62.2 | 5.14.21-150500.55.62.2 |
| openSUSE:Leap 15.5 | kernel-default-base | before 5.14.21-150500.55.62.2.150500.6.27.2 | 5.14.21-150500.55.62.2.150500.6.27.2 |
| openSUSE:Leap 15.5 | kernel-docs | before 5.14.21-150500.55.62.2 | 5.14.21-150500.55.62.2 |
| openSUSE:Leap 15.5 | kernel-kvmsmall | before 5.14.21-150500.55.62.2 | 5.14.21-150500.55.62.2 |
| openSUSE:Leap 15.5 | kernel-obs-build | before 5.14.21-150500.55.62.2 | 5.14.21-150500.55.62.2 |
| openSUSE:Leap 15.5 | kernel-obs-qa | before 5.14.21-150500.55.62.1 | 5.14.21-150500.55.62.1 |
| openSUSE:Leap 15.5 | kernel-rt | before 5.14.21-150500.13.52.1 | 5.14.21-150500.13.52.1 |
| openSUSE:Leap 15.5 | kernel-rt_debug | before 5.14.21-150500.13.52.1 | 5.14.21-150500.13.52.1 |
| openSUSE:Leap 15.5 | kernel-source | before 5.14.21-150500.55.62.2 | 5.14.21-150500.55.62.2 |
| openSUSE:Leap 15.5 | kernel-source-rt | before 5.14.21-150500.13.52.1 | 5.14.21-150500.13.52.1 |
| openSUSE:Leap 15.5 | kernel-syms | before 5.14.21-150500.55.62.1 | 5.14.21-150500.55.62.1 |
| openSUSE:Leap 15.5 | kernel-syms-rt | before 5.14.21-150500.13.52.1 | 5.14.21-150500.13.52.1 |
| openSUSE:Leap 15.5 | kernel-zfcpdump | before 5.14.21-150500.55.62.2 | 5.14.21-150500.55.62.2 |
| openSUSE:Leap Micro 5.3 | kernel-default | before 5.14.21-150400.24.119.1 | 5.14.21-150400.24.119.1 |
| openSUSE:Leap Micro 5.3 | kernel-default-base | before 5.14.21-150400.24.119.1.150400.24.56.1 | 5.14.21-150400.24.119.1.150400.24.56.1 |
| openSUSE:Leap Micro 5.3 | kernel-rt | before 5.14.21-150400.15.79.1 | 5.14.21-150400.15.79.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | kernel-64kb | before 5.14.21-150400.24.119.1 | 5.14.21-150400.24.119.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | kernel-docs | before 5.14.21-150400.24.119.1 | 5.14.21-150400.24.119.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | kernel-obs-build | before 5.14.21-150400.24.119.1 | 5.14.21-150400.24.119.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | kernel-source | before 5.14.21-150400.24.119.1 | 5.14.21-150400.24.119.1 |
+21
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-2021-47187Apr 10, 2024 · arm64: dts: qcom: msm8998: Fix CPU/L2 idle state latency and residency22Monitor
- ← EarlierCVE-2021-47188Apr 10, 2024 · scsi: ufs: core: Improve SCSI abort handling22Monitor
- Later →CVE-2021-47190Apr 10, 2024 · perf bpf: Avoid memory leak from perf_env__insert_btf()22Monitor
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 | 45da9c1767ac31857df572f0a909fbe88fd5a7e9 | Vendor (CNA) |
| Linux Linux | 47e6f9f69153247109042010f3a77579e9dc61ff | Vendor (CNA) |
| Linux Linux | 637d652d351fd4f263ef302dc52f3971d314e500 | Vendor (CNA) |
| Linux Linux | 670f6b3867c8f0f11e5097f353b164cecfec6179 | Vendor (CNA) |
| Linux Linux | 6adbc07ebcaf8bead08b21687d49e0fc94400987 | Vendor (CNA) |
| Linux Linux | 804a9d239ae9cbe88e861a7cd62319cc6ec7b136 | Vendor (CNA) |
| Linux Linux | bd660a20fea3ec60a49709ef5360f145ec0fe779 | Vendor (CNA) |
| Linux Linux | ed058d735a70f4b063323f1a7bb33cda0f987513 | Vendor (CNA) |
| debian:linux | 5.15.5-1 · Debian:12 | Package registry (OSV) |
| opensuse:dtb-aarch64 | 5.14.21-150500.55.62.1 · openSUSE:Leap 15.5 | Package registry (OSV) |
| opensuse:kernel-64kb | 5.14.21-150500.55.62.2 · openSUSE:Leap 15.5 | Package registry (OSV) |
| opensuse:kernel-debug | 5.14.21-150500.55.62.2 · openSUSE:Leap 15.5 | Package registry (OSV) |
| opensuse:kernel-default | 5.14.21-150400.24.119.1 · openSUSE:Leap Micro 5.3 | Package registry (OSV) |
| opensuse:kernel-default-base | 5.14.21-150400.24.119.1.150400.24.56.1 · openSUSE:Leap Micro 5.3 | Package registry (OSV) |
| opensuse:kernel-docs | 5.14.21-150500.55.62.2 · openSUSE:Leap 15.5 | Package registry (OSV) |
| opensuse:kernel-kvmsmall | 5.14.21-150500.55.62.2 · openSUSE:Leap 15.5 | Package registry (OSV) |
| opensuse:kernel-obs-build | 5.14.21-150500.55.62.2 · openSUSE:Leap 15.5 | Package registry (OSV) |
| opensuse:kernel-obs-qa | 5.14.21-150500.55.62.1 · openSUSE:Leap 15.5 | Package registry (OSV) |
| opensuse:kernel-rt | 5.14.21-150400.15.79.1 · openSUSE:Leap Micro 5.3 | Package registry (OSV) |
| opensuse:kernel-source | 5.14.21-150500.55.62.2 · openSUSE:Leap 15.5 | Package registry (OSV) |
| opensuse:kernel-syms | 5.14.21-150500.55.62.1 · openSUSE:Leap 15.5 | Package registry (OSV) |
| suse:kernel-64kb | 5.14.21-150400.24.119.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | Package registry (OSV) |
| suse:kernel-default | 5.14.21-150400.24.119.1 · SUSE:Linux Enterprise Micro 5.3 | Package registry (OSV) |
| suse:kernel-default-base | 5.14.21-150400.24.119.1.150400.24.56.1 · SUSE:Linux Enterprise Micro 5.3 | Package registry (OSV) |
| suse:kernel-docs | 5.14.21-150400.24.119.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | Package registry (OSV) |
| suse:kernel-livepatch-SLE15-SP4_Update_26 | 1-150400.9.3.1 · SUSE:Linux Enterprise Live Patching 15 SP4 | Package registry (OSV) |
| suse:kernel-livepatch-SLE15-SP5_Update_13 | 1-150500.11.3.2 · SUSE:Linux Enterprise Live Patching 15 SP5 | Package registry (OSV) |
| suse:kernel-obs-build | 5.14.21-150400.24.119.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | Package registry (OSV) |
| suse:kernel-rt | 5.14.21-150400.15.79.1 · SUSE:Linux Enterprise Micro 5.3 | Package registry (OSV) |
| suse:kernel-source | 5.14.21-150400.24.119.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | Package registry (OSV) |
+3
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-24-0494 · May 16, 2024(Linux Kernel Güncellemesi)
- TR-24-0284 · Apr 15, 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
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
—
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
nvd-secondary
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 (7 more)Show less
- git.kernel.org/stable/c/47e6f9f69153247109042010f3a77579e9dc61ff
- git.kernel.org/stable/c/637d652d351fd4f263ef302dc52f3971d314e500
- git.kernel.org/stable/c/670f6b3867c8f0f11e5097f353b164cecfec6179
- git.kernel.org/stable/c/6adbc07ebcaf8bead08b21687d49e0fc94400987
- git.kernel.org/stable/c/804a9d239ae9cbe88e861a7cd62319cc6ec7b136
- git.kernel.org/stable/c/bd660a20fea3ec60a49709ef5360f145ec0fe779
- git.kernel.org/stable/c/ed058d735a70f4b063323f1a7bb33cda0f987513
Vendor advisories and official records. Exploit/PoC links are deliberately left out.