Security readout for executives and security teams
Plain-English summary
Incus versions before 7.1.0 contain a critical flaw in the S3 multipart upload endpoint. A low-privileged attacker able to reach and use that endpoint could create files in unintended host locations. This may enable command execution, potentially compromising the host and its managed workloads.
Executive priority
Treat this as an immediate remediation priority for reachable Incus deployments. The flaw crosses from a managed upload interface to host file creation, with possible command execution and full security impact. Confirm inventory and upgrade status promptly; escalate any unexplained host changes for incident investigation.
Technical view
CVE-2026-48753 is a path-traversal arbitrary-file-write vulnerability in Incus’s S3 protocol multipart upload endpoint. It affects versions earlier than 7.1.0. The CVSS 3.1 score is 9.9, reflecting network access, low complexity, low privileges, no user interaction, changed scope, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure exists where Incus earlier than 7.1.0 is deployed and the vulnerable S3 multipart upload endpoint is reachable by a low-privileged user. The supplied sources do not identify affected configurations, default endpoint exposure, or required account permissions beyond the CVSS low-privilege rating.
Exploitation context
The vulnerability permits arbitrary host file creation through path traversal and could lead to command execution. The supplied record is not in KEV, and no cited source establishes active exploitation. Public exploit availability is not established by the provided evidence.
Researcher notes
The weakness is classified as CWE-73 and involves externally controlled file paths. The record establishes arbitrary host file creation but does not provide enough evidence to characterize traversal constraints, target paths, authentication specifics, exploitation reliability, or observed attacks. Validate defensively without attempting host modification.
Mitigation direction
- Upgrade affected Incus installations to version 7.1.0 or later.
- Prioritize internet-accessible or broadly reachable S3 upload endpoints.
- If upgrading is delayed, restrict endpoint access and consult the vendor advisory for supported mitigations.
- Review access granted to low-privileged Incus users until remediation is complete.
Validation and detection
- Inventory Incus installations and confirm each reported version.
- Verify no installation remains below version 7.1.0.
- Identify whether the S3 multipart upload endpoint is enabled and network reachable.
- Review host files and relevant logs for unexpected activity associated with multipart uploads.
- Recheck exposure after upgrading using non-destructive validation.
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-73: File access and web shell behavior lookup
File traversal and upload weaknesses can lead teams to review file, web shell, execution, and collection telemetry. 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 lookupFile access behavior lookup
The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupContainer behavior lookup
The affected technology mentions containers, so container-specific ATT&CK technique review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-48753 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
- Critical
- CVSS
- 9.9 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/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:L/UI:N/S:C/C:H/I:H/A:H3.16GitHub_MVulnerability scoring details
Base CVSS 3.1 score
9.9CriticalVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/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://github.com/lxc/incus/security/advisories/GHSA-ccjc-4qc3-jxqcCVE reference, GitHub_M · x_refsource_CONFIRM
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.
External Control of File Name or Path
External Control of File Name or Path represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.