vulnerability / NVI-00017721 / Revision 1
Incus has an argument injection in backup compression algorithm leading to AFW and ACE
GitHub lists this reviewed advisory for github.com/lxc/incus/v7/cmd/incusd. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
9.9 critical
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
github.com/lxc/incus/v7/cmd/incusd
source listed< 7.2.0
### 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 `compression_algorithm` by parsing it into fields and checking only the first token against an allowlist: ```go fields, err := shellquote.Split(value) ... if !slices.Contains([]string{"bzip2", "gzip", "lz4", "lzma", "pigz", "pzstd", "pxz", "tar2sqfs", "xz", "zstd"}, fields[0]) { return fmt.Errorf("Compression algorithm %q isn't currently supported", fields[0]) } _, err = exec.LookPath(fields[0]) ``` Extra arguments are not rejected. `compressFile()` then prepends `-c` and passes the remaining user-supplied fields to the compressor: ```go args := []string{"-c"} if len(fields) > 1 { args = append(args, fields[1:]...) } cmd := exec.Command(fields[0], args...) cmd.Stdin = infile cmd.Stdout = outfile ``` With a value like: ```text zstd -d -f --pass-through -o /etc/cron.d/incus-zstd-rce -- /var/lib/incus/.../payload ``` the daemon executes the equivalent of: ```text zstd -c -d -f --pass-through -o /etc/cron
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
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04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
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- GHSA-v6mj-8pf4-hhw4 ↗
GitHub Advisory Database · vendor advisory
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Public revision history
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- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.