CVE-2026-48753 — Incus has an arbitrary file write via path traversal in S3 multipart upload
Incus is a system container and virtual machine manager. Prior to version 7.1.0, the S3 protocol upload endpoint is vulnerable to path traversal and allows creation of arbitrary files on the host. This behavior could lead to arbitrary command execution. Version 7.1.0 fixes the issue.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.7% (30-day exploitation probability)+8
- Technical severity (critical)+10
- CISA SSVC: exploitation "poc"+5
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Go Github.com/lxc/incus/v7/cmd/incusd: fixed in version 7.1.0 — github.com (GitHub Security Advisories)
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Lxc Incus, Go Github.com/lxc/incus/v7/cmd/incusd).
- Apply the fixed version or the patch documented under Remediation.
- Search available logs for exploit probes, errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Lxc | Incus | version < 7.1.0 | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Go | Github.com/lxc/incus/v7/cmd/incusd | < 7.1.0 | Vulnerable | GitHub Security Advisories |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 9.9 | CVSS 3.1 | Critical | 3.1 | 6.0 | security-advisories@github.com via NIST National Vulnerability Database |
| 9.9 | CVSS 3.1 | Critical | — | — | GitHub, Inc. via GitHub Security Advisories |
| 9.9 | CVSS 3.1 | Critical | — | — | GitHub_M via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H (score shown at the top: security-advisories@github.com) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Timeline
What happened to this CVE, newest first.
- 2026
- Fix documented
- Affected products added · go/github.com/lxc/incus/v7/cmd/incusd
- Affected products added · lxc/incus
- SSVC assessment updated
- Record published
- CVSS changed · 9.9
- Source status changed · → Deferred
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 2× References added · Oct 15, 2026 – Oct 15, 2026
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
2 on the record
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-63343 Arbitrary File Read/Write: metadata.yaml symlink in image allows host filesystem access as root Aug 21, 2026
- Critical CVE-2026-62941 Incus: Cross-project instance copy bypasses target project restrictions via TOCTOU in config merge Aug 21, 2026
- Critical CVE-2026-63125 Incus vulnerable to root RCE via image backup.yaml symlink Aug 21, 2026
- Critical CVE-2026-62940 Incus has a project restriction bypass via instance migration config override Aug 21, 2026
- Critical CVE-2026-62867 Incus has an argument injection in storage volume block.create_options that leads to arbitrary command execution Aug 21, 2026
- Medium CVE-2026-62313 Incus: Project restriction `restricted.containers.privilege=isolated` bypassable by omitting `security.idmap.isolated` Aug 21, 2026
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-48753 is "Incus has an arbitrary file write via path traversal in S3 multipart upload", rated Critical. It affects Incus (Lxc); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 9.9 describes technical severity. EPSS 0.73% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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