CVE-2026-63343

CRITICALPre-NVD 9.99.9—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 82% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 3 sources updated this week
9.9EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.9Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Incus is a system container and virtual machine manager. Prior to version 7.3.0, a malicious image containing a metadata.yaml symlink pointing to an arbitrary host path allows an authenticated Incus user to read or overwrite any file on the host as root via the instance metadata API. The exec-output and templates/ paths were patched in a prior release using Lstat rejection and os.OpenRoot confinement; metadata.yaml was not included in either patch and remains exploitable. Version 7.3.0 patches the issue.

CVSS v3
9.9
EG Score
9.9(medium)
EG Risk
45(Track)
EG Risk 45/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity99% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
18%
KEV
Not listed

Published

August 21, 2026

Last Modified

August 21, 2026

Advisory Details (1)

Auto-updated Aug 21, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

Arbitrary file read+write on host via metadata.yaml symlink in crafted image · Advisory · lxc/incus · GitHub

https://github.com/lxc/incus/security/advisories/GHSA-fmjx-5j3g-997p

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 11× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-25 17:09 UTCEG score recompute
  2. 2026-08-25 13:49 UTCEPSS rescore
  3. 2026-08-24 17:15 UTCEG score recompute
  4. 2026-08-24 13:20 UTCEG score recompute
  5. 2026-08-23 01:57 UTCEG score recompute
  6. 2026-08-23 00:19 UTCEPSS rescore
  7. 2026-08-21 22:25 UTCEG score recompute
  8. 2026-08-21 21:52 UTCEG score recompute
  9. 2026-08-21 15:21 UTCEG score recompute
  10. 2026-08-21 15:10 UTCEG score recompute
  11. 2026-08-21 15:09 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-63343?
CVE-2026-63343 is a critical vulnerability published on August 21, 2026. Incus is a system container and virtual machine manager. Prior to version 7.3.0, a malicious image containing a metadata.yaml symlink pointing to an arbitrary host path allows an authenticated Incus user to read or overwrite any file on the host as root via the instance metadata API. The…
When was CVE-2026-63343 disclosed?
CVE-2026-63343 was first published in the National Vulnerability Database on August 21, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-63343 actively exploited?
CVE-2026-63343 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 81.7% of all scored CVEs.
What is the CVSS score of CVE-2026-63343?
CVE-2026-63343 has a CVSS v3 base score of 9.9 (NVD).
How do I remediate CVE-2026-63343?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-63343, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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