Security readout for executives and security teams
Plain-English summary
CVE-2025-21833 is a Linux kernel availability bug in the VT-d IOMMU code. In an unusual error case, the kernel may continue after a warning and use a NULL pointer. The stated impact is local denial of service, not data theft or privilege escalation.
Executive priority
Treat this as a standard kernel patching item with higher priority for shared Linux infrastructure. Business risk is service disruption from local abuse, not confirmed remote compromise or data exposure.
Technical view
The issue is CWE-476 in iommu/vt-d domain_remove_dev_pasid handling. If a PASID lookup unexpectedly fails, WARN_ON_ONCE can be hit, but the code must avoid dereferencing the resulting NULL pointer. CVSS 3.1 is 5.5: local access, low privileges, no user interaction, high availability impact.
Likely exposure
Exposure is most relevant to Linux systems running affected kernel versions with the VT-d IOMMU code path present. The bundle does not identify affected distributions, cloud images, appliances, or configuration prerequisites beyond Linux kernel version data.
Exploitation context
The source bundle does not show active exploitation, public exploit details, or KEV listing. CVSS indicates a low-privileged local attacker could trigger availability impact, but the bundle does not provide operational exploit conditions.
Researcher notes
Evidence is limited to the CVE record and upstream stable commits. The key condition is failure to find a PASID in domain_remove_dev_pasid, followed by potential NULL use. No exploit technique, distribution mapping, or workaround is provided in the bundle.
Mitigation direction
- Update to a vendor kernel build containing the referenced stable fixes.
- Check Linux distribution advisories before relying on upstream commit status alone.
- Prioritize multi-user, shared compute, and untrusted workload hosts.
- Reduce local access to trusted users while awaiting vendor-fixed kernels.
Validation and detection
- Inventory running Linux kernel versions against vendor advisories for CVE-2025-21833.
- Confirm whether kernel changelogs include the stable fix commits listed in the CVE record.
- Identify systems where untrusted users or workloads have local execution.
- Do not mark active exploitation unless a cited source or KEV later supports it.
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-476: 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-2025-21833 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.
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:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H1.83.6CISA-ADPVulnerability 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
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/68ec78beb4a3fb0877cbaaf49758c85410c05977CVE reference, Linux
- https://git.kernel.org/stable/c/df96876be3b064aefc493f760e0639765d13ed0dCVE reference, Linux
- https://git.kernel.org/stable/c/60f030f7418d3f1d94f2fb207fe3080e1844630bCVE 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.
NULL Pointer Dereference
NULL Pointer Dereference represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.