Security readout for executives and security teams
Plain-English summary
A bug in Linux io_uring link timeout request handling could mishandle internal reference counts during a race. The public record shows a kernel warning and fix, but does not provide a CVSS score, confirmed impact, or exploitation evidence. Treat this as a kernel maintenance exposure until vendor guidance clarifies severity.
Executive priority
Schedule this through normal kernel patch governance unless the environment has high-risk shared Linux hosts or vendor guidance assigns higher severity. There is no supplied evidence of exploitation, but kernel bugs can carry broad operational impact if left unpatched.
Technical view
CVE-2021-47124 is a Linux kernel io_uring reference-counting flaw. In a race with master request completion, io_link_timeout_fn could release more references than intended after io_req_complete and io_put_req_deferred paths. The source identifies affected Linux kernel versions and stable kernel fixes, but not a CWE, CVSS vector, or concrete security impact.
Likely exposure
Exposure is most plausible on systems running affected Linux kernel versions with io_uring available. The bundle lists Linux 5.10.43, 5.10.55, 5.12, 5.12.10, 5.12.19, 5.13, and related commits as affected; distribution package mapping must be verified separately.
Exploitation context
The provided sources do not show active exploitation, public exploit code, or inclusion in KEV. They describe a kernel race and refcount warning resolved by stable commits. Any exploitability beyond the recorded bug is not established in the supplied evidence.
Researcher notes
The record is evidence-limited: no CVSS, CWE, or confirmed impact is provided. Analysis should focus on mapping distro kernels to the stable commits and understanding whether io_uring exposure exists in the target environment. Do not infer exploitability from the refcount warning alone.
Mitigation direction
- Apply Linux kernel updates that include the referenced stable fixes.
- Check your Linux distribution advisory for CVE-2021-47124 package mappings.
- Prioritize internet-facing, multi-user, and container-host kernels for review.
- Avoid claiming remediation from version strings alone; verify backported fixes.
Validation and detection
- Inventory kernel versions across servers, workstations, and container hosts.
- Compare installed kernel packages against vendor CVE-2021-47124 advisories.
- Check package changelogs for the referenced stable commit IDs.
- Review kernel logs for matching refcount warnings if instability was observed.
Public sources used
- CVE Program
- CVE List V5
- Linux stable commit 0b2a990e5d2f76d020cb840c456e6ec5f0c27530
- Linux stable commit 6f5d7a45f58d3abe3a936de1441b8d6318f978ff
- Linux stable commit 876808dba2ff7509bdd7f230c4f374a0caf4f410
- Linux stable commit ff4a96ba5c8f9b266706280ff8021d2ef3f17e86
- Linux stable commit a298232ee6b9a1d5d732aa497ff8be0d45b5bd82
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CVE-2021-47124 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://git.kernel.org/stable/c/0b2a990e5d2f76d020cb840c456e6ec5f0c27530CVE reference, Linux
- https://git.kernel.org/stable/c/6f5d7a45f58d3abe3a936de1441b8d6318f978ffCVE reference, Linux
- https://git.kernel.org/stable/c/876808dba2ff7509bdd7f230c4f374a0caf4f410CVE reference, Linux
- https://git.kernel.org/stable/c/ff4a96ba5c8f9b266706280ff8021d2ef3f17e86CVE reference, Linux
- https://git.kernel.org/stable/c/a298232ee6b9a1d5d732aa497ff8be0d45b5bd82CVE reference, Linux
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.