Security readout for executives and security teams
Plain-English summary
CVE-2021-47241 is a Linux kernel ethtool netlink bug where the kernel can underestimate a response size. Under narrow device and request conditions, this can trigger a kernel warning and splat, creating an availability concern rather than a known data theft or privilege escalation issue.
Executive priority
Treat this as a high-priority availability patch for Linux systems, especially infrastructure with network device management exposure. It is not documented here as actively exploited, but kernel availability issues deserve normal expedited remediation.
Technical view
The issue is in ethtool string-set handling: the outer ETHTOOL_A_STRSET_STRINGSETS nest was not included in message length calculation. The source says ETHTOOL_MSG_STRSET_GET can produce an insufficient payload warning when specific skb sizing, per-device string set, and long device-name conditions align.
Likely exposure
Systems running affected Linux kernel versions or unpatched vendor kernels may be exposed, especially where ethtool netlink queries against network devices are possible. Confirm exposure against kernel build, distribution backports, and the linked stable fixes.
Exploitation context
The bundle does not show CISA KEV listing or confirmed active exploitation. The description frames triggering conditions as narrow and notes current user space appears mainly relevant when reading private flags, with syzbot-style discovery also mentioned.
Researcher notes
Evidence is limited to the CVE record and kernel stable references. The described trigger requires multiple conditions, including no skb rounding, per-device string set header population, and a device name of at least 12 characters.
Mitigation direction
- Update to a kernel containing the referenced stable ethtool strset fixes.
- Check Linux distribution advisories for backported fixes before judging by version alone.
- Limit unnecessary local or remote access to ethtool-capable management interfaces.
- Monitor kernel logs for repeated ethtool netlink warning or splat patterns.
Validation and detection
- Inventory Linux kernel versions across servers, appliances, and network-focused hosts.
- Compare deployed kernel packages against vendor advisories and linked stable commits.
- Review kernel logs for ETHTOOL_MSG_STRSET_GET payload length warnings.
- Confirm whether long network device names and per-device string sets exist.
Public sources used
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
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CWE-266: Exact CWE lookup
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Open ATT&CK lookupCVE-2021-47241 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
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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/fb3a948143688e14e2cfd2a2812877923d0e5e92CVE reference, Linux
- https://git.kernel.org/stable/c/cfc7f0e70d649e6d2233fba0d9390b525677d971CVE reference, Linux
- https://git.kernel.org/stable/c/e175aef902697826d344ce3a12189329848fe898CVE 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.
Incorrect Privilege Assignment
Incorrect Privilege Assignment represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.