Project Existence Disclosure via Error Handling in LXD Image Export

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

Information disclosure in image export API in Canonical LXD before 6.5 and 5.21.4 on Linux allows network attackers to determine project existence without authentication via crafted requests using wildcard fingerprints.

Source published

2 Oct 2025 09:24:12 UTC

Source modified

2 Oct 2025 17:31:02 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 4.0 · 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Information disclosure in image export API in Canonical LXD before 6.5 and 5.21.4 on Linux allows network attackers to determine project existence without authentication via crafted requests using wildcard fingerprints.

Source published

Oct 2, 2025, 9:24:12 AM (timezone not stated)

Source modified

Oct 2, 2025, 5:31:02 PM (timezone not stated)

Observed here

9 Nov 2026 03:10:03 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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EUVD CVSS 4.0 · 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Information disclosure in image export API in Canonical LXD before 6.5 and 5.21.4 on Linux allows network attackers to determine project existence without authentication via crafted requests using wildcard fingerprints.

Source published

2 Oct 2025 10:15:39 UTC

Source modified

12 Oct 2026 15:10:00 UTC

Observed here

25 Oct 2026 02:25:06 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS 3.1 · [email protected] · Primary · 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

### Impact In LXD's images export API (`/1.0/images/{fingerprint}/export`), implementation differences in error handling allow determining project existence without authentication. Specifically, in the following code, errors when multiple images match are directly returned to users as API responses: https://github.com/canonical/lxd/blob/43d5189564d27f6161b430ed258c8b56603c2759/lxd/db/images.go#L239-L246 While fingerprints generally don't duplicate, this functionality uses fingerprints with LIKE clauses, allowing prefix specification. Therefore, using LIKE wildcards such as % will match multiple images if multiple images exist in the project. https://github.com/canonical/lxd/blob/43d5189564d27f6161b430ed258c8b56603c2759/lxd/db/images.go#L277-L286 In the above implementation, multiple matches result in a 500 error, but if the project itself doesn't exist, there are 0 matches and a 404 is returned. 1. When project exists and multiple images match: HTTP 500 error "More than one image matches" 2. When project doesn't exist: HTTP 404 error "not found" This behavioural difference allows attackers to confirm project existence without authentication. ### Reproduction Steps 1. Send a request with a pattern matching multiple entries to an existing project (default): ``` curl -k 'https://lxd-host:8443/1.0/images/%25/export?project=default&secret=x' ``` Response: ```json {"type":"error","status":"","status_code":0,"operation":"","error_code":500,"error":"More than one image matches","metadata":null} ``` 2. Send a same request to a non-existent project (not-exist): ``` curl -k 'https://lxd-host:8443/1.0/images/%25/export?project=not-exist&secret=x' ``` Response: ```json {"type":"error","status":"","status_code":0,"operation":"","error_code":404,"error":"not found","metadata":null} ``` This difference allows enumerating existing projects in the system by brute-forcing(dictionary attack) project names. Note that `%25` is the URL encoding of `%`, which works as a wildcard matching all characters in SQL LIKE clauses. This is used to intentionally create requests matching multiple images to trigger a 500 error. Additionally, the secret parameter is added to include non-public images in the search, increasing the possibility of multiple matches. https://github.com/canonical/lxd/blob/43d5189564d27f6161b430ed258c8b56603c2759/lxd/images.go#L4211-L4230 ### Risk The attack requires only network access to the LXD API endpoint, with no authentication needed. The attack allows confirming the existence of projects within the LXD system by exploiting differences in HTTP status codes. This could potentially increase the exploitability of other vulnerabilities. Additionally, since project IDs often use meaningful names set by users, this could lead to leakage of unpublished product information. However, resource information within projects cannot be obtained, limiting the impact to existence confirmation only. ### Countermeasures It is recommended to modify error handling in the images export API (`/1.0/images/{fingerprint}/export`) to return consistent responses regardless of project existence. Specifically, return 404 even when errors occur during project existence verification. This ensures the same error response is returned for both existing and non-existing projects, preventing determination of project existence. Additionally, if there are no specification(compatibility) issues, allowing only exact fingerprint matches in unauthenticated states and disabling prefix matching can prevent unexpected errors from occurring. ### Patches | LXD Series | Status | | ------------- | ------------- | | 6 | Fixed in LXD 6.5 | | 5.21 | Fixed in LXD 5.21.4 | | 5.0 | Ignored - Not critical | | 4.0 | Ignored - EOL and not critical | ### References Reported by GMO Flatt Security Inc.

Source published

2 Oct 2025 21:16:27 UTC

Source modified

10 Sep 2026 03:50:30 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Publisher rating · MODERATE

Canonical LXD Project Existence Determination Through Error Handling in Image Export Function in github.com/canonical/lxd

Source published

5 Nov 2025 18:41:07 UTC

Source modified

5 Nov 2025 19:57:14 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.