Incus: Arbitrary file write via symlink in migration stream
Summary
Incus before 6.0.7, 6.1.0 before 7.0.2 and 7.1.0 before 7.5.0 allow a malicious migration source to write arbitrary files to the host as root. The rsync and btrfs receive paths follow symlinks planted in the transferred volume, for example a rootfs symlink pointing to /. An attacker who can create instances or custom volumes in a project, or who controls a server the target copies or moves from, can achieve full host compromise. Releases before 7.3.0 can additionally read host files through a surviving rootfs symlink.
Affected
- Incus before 6.0.7
- Incus 6.1.0 before 7.0.2
- Incus 7.1.0 before 7.5.0
- Distribution builds may carry backported patches; check the package changelog.
Fixed in
- Upstream: 6.0.7, 7.0.2 and 7.5.0
- Distribution packages: use the fixed build from your distribution (for example a backported package).
Workaround
- Unknown. No vendor-documented workaround was found.
- Interim measure (not from the vendor): only allow trusted clients to create instances and custom volumes, and only migrate, copy or import from trusted servers.
Exploitation
- No evidence of in-the-wild exploitation found in the sources checked. CISA KEV was not checked.
- No public proof of concept found for this CVE.
- CISA SSVC: exploitation none, automatable no, technical impact total.
- A related Incus symlink issue (CVE-2026-48749) has public write-ups, so the bug class is known.
Our recommendation
- Inventory Incus hosts and versions, including distribution packages.
- Upgrade to 6.0.7, 7.0.2 or 7.5.0, or to your distribution's fixed package.
- Until patched, restrict migration, copy and import rights and accept remote sources only from trusted hosts.
- Monitor the vendor advisory GHSA-579w-c4rw-c8q3 and CISA KEV for status changes.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- GitHub Security Advisory GHSA-579w-c4rw-c8q3 github.com
- VulnCheck advisory CVE-2026-115377 www.vulncheck.com
- Incus 6.0.7 LTS release announcement discuss.linuxcontainers.org
- Incus fix pull request #4071 github.com
- Incus news linuxcontainers.org
- Debian backports security update BSA-139 backports.debian.org
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 30 Oct 2026, 23:56.
Original description (NVD)
Incus before 6.0.7, 6.1.0 before 7.0.2, and 7.1.0 before 7.5.0 contains an arbitrary file write vulnerability that allows malicious migration sources to write host files by planting symlinks in transferred volumes. Attackers can craft rsync or btrfs receive streams with a symlink such as rootfs pointing to the host root, writing files as root for full host compromise.
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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