Security readout for executives and security teams
Plain-English summary
This Linux kernel flaw can let a low-privileged local attacker crash or hang affected systems by triggering unbounded recursion in Netlink attribute policy handling. The business impact is availability loss, not data theft or tampering. It matters most on shared Linux systems where local users or processes are not fully trusted.
Executive priority
Treat this as a moderate availability risk. It is not evidence of a remote breach path, but unpatched shared Linux systems could be disrupted by low-privileged local access. Patch through normal kernel maintenance, with faster handling for shared or high-availability systems.
Technical view
CVE-2020-36691 affects Linux kernel versions before 5.8 in lib/nlattr.c. A nested Netlink policy containing a back reference can cause unbounded recursion, classified as CWE-674. CVSS 3.1 is 5.5 with local access, low privileges, no user interaction, and high availability impact only.
Likely exposure
Exposure is likely limited to Linux systems running kernels before 5.8 or vendor kernels without the relevant backport. The source bundle does not identify specific distributions, appliances, or cloud services. Prioritize multi-user servers and systems where low-privileged local code may run.
Exploitation context
The source bundle does not show CISA KEV listing or other evidence of active exploitation. Exploitation requires local access with low privileges and targets availability. No remote attack path is supported by the provided CVSS vector or description.
Researcher notes
Evidence supports a local denial-of-service issue caused by unbounded recursion in Netlink attribute policy validation. The public record is sparse: affected distribution matrices, exploit maturity, and operational mitigations are not provided in the source bundle.
Mitigation direction
- Upgrade to Linux kernel 5.8 or a vendor-supported kernel containing the fix.
- Confirm distribution backport status using vendor kernel advisories or changelogs.
- Reduce exposure from untrusted local users where patching is delayed.
- Prioritize patching shared servers and systems running untrusted local workloads.
- Monitor vendor guidance for any distribution-specific remediation details.
Validation and detection
- Inventory Linux kernel versions across affected environments.
- Flag systems running kernels before 5.8 for vendor backport review.
- Check whether vendor kernel packages include commit 7690aa1cdf7c4565ad6b013b324c28b685505e24 or equivalent.
- Verify patched systems remain stable using normal regression and availability checks.
- Document exceptions where patching depends on vendor guidance.
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
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-674: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2020-36691 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
- Medium
- CVSS
- 5.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/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.
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:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H1.83.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.5MediumVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Source materials
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.
Uncontrolled Recursion
Uncontrolled Recursion represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.