Security Digest · Vulnerability record
CVE-2026-48755: Incus has an argument injection in backup compression algorithm leading to AFW and ACE
Incus is a system container and virtual machine manager.
CVSS 9.9 Critical EPSS 0.7% · p54
Should you act?
Critical, preconditions apply
Severe if exploited, but exploitation needs conditions that may not apply to you. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.7%, percentile 54: FIRST’s model estimates a 0.7% chance of exploitation activity in the next 30 days, higher than 54% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Needs an account (low (any account)). Exposure depends on who can log in.
- Only applies if your dependency tree includes
github.com/lxc/incus/v7/cmd/incusd(Go) < 7.2.0, fixed in 7.2.0. Check your lockfile, including transitive dependencies.
What it is
Incus is a system container and virtual machine manager. Prior to version 7.1.0, improper validation of user-provided backup compression algorithm leads to argument injection in the constructed command line. This leads to an arbitrary file write on the host, possibly leading to arbitrary command execution. Version 7.1.0 patches the issue.
From the GitHub advisory
Summary
Improper validation of user-provided backup compression algorithm leads to argument injection in the constructed command line. This leads to an arbitrary file write on the host, possibly leading to arbitrary command execution.
Details
Incus validates compressionalgorithm by parsing it into fields and checking only the first token against an allowlist:
Extra arguments are not rejected. compressFile() then prepends -c and passes the remaining user-supplied fields to the compressor:
Weakness type: CWE-20.
Product: github.com/lxc/incus/v7/cmd/incusd (Go) · Assigned by: GitHub_M · Published: 2026-08-21
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| Go | github.com/lxc/incus/v7/cmd/incusd | < 7.2.0 | 7.2.0 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| lxc | incus | < 7.2.0 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 3.1 | 9.9 Critical | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H |
| GitHub | 3.1 | 9.9 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: low (any account)
- User interaction: none
- Scope: changed (can affect other components)
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none, automatable no, technical impact total.
- FIRST EPSS (model of 2026-10-21): 0.73% probability of exploitation activity in the next 30 days; percentile 54.
Timeline
- — GitHub-reviewed advisory GHSA-v6mj-8pf4-hhw4 published (critical)
- — CVE record last updated
- — CVE record published by GitHub_M
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-v6mj-8pf4-hhw4 github.com
- CVE.org record CVE-2026-48755 cve.org
- NVD entry CVE-2026-48755 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com