Crossplane: Signature verification TOCTOU allows installing unverified package content via mutable tag
## Summary Crossplane allows package signature verification to be configured via the `ImageConfig` mechanism. When enabled, the package manager uses cosign to verify that packages are correctly signed before pulling and installing them. When a package is installed using a tag reference (e.g., a semantic version), a malicious OCI registry could serve a correctly signed image for verification, then subsequently serve an unsigned image for installation. This is possible because Crossplane resolves the tag reference separately for each step. This vulnerability is relevant only for users who do all three of the following: 1. Configure signature verification for packages, 2. Install packages using tag references rather than digests, and 3. Install packages from registries they do not control. ## Mitigation Installing packages by image digest rather than using tags avoids this issue. ## Fix The package manager has been updated to resolve tag references once and use the resulting digest for both signature verification and image fetching. This ensures that Crossplane pulls the same content that had its signature verified. The fix has been applied to Crossplane's `main` branch and backported to the v2.3 and v2.2 release branches; it will be released in v2.3.3 and v2.2.3. ## Note on Fixed Versions The Crossplane maintainers are *not* planning to backport the fix for this advisory to the 1.20 branch, for two reasons: 1. The advisory is relevant only when an alpha feature is enabled and c
GHSA-wfqx-gjrf-g28r
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: osv:GHSA-wfqx-gjrf-g28r
github.com/crossplane/crossplane/v2
Source reference: /affected/0/package/name
- Affected versions
- Not stated in this record
- Fixed versions
- 2.3.3
Source reference:
/affected/0/ranges - Prerequisites
- Not stated in this record
github.com/crossplane/crossplane/v2
Source reference: /affected/1/package/name
- Affected versions
- Not stated in this record
- Fixed versions
- 2.2.3
Source reference:
/affected/1/ranges - Prerequisites
- Not stated in this record
github.com/crossplane/crossplane
Source reference: /affected/2/package/name
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"ranges": [
{
"type": "SEMVER",
"events": [
{
"introduced": "2.3.0-rc.0"
},
{
"fixed": "2.3.3"
}
]
}
],
"package": {
"name": "github.com/crossplane/crossplane/v2",
"purl": "pkg:golang/github.com/crossplane/crossplane/v2",
"ecosystem": "Go"
},
"database_specific": {
"source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-wfqx-gjrf-g28r/GHSA-wfqx-gjrf-g28r.json",
"last_known_affected_version_range": "<= 2.3.2"
}
},
{
"ranges": [
{
"type": "SEMVER",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.2.3"
}
]
}
],
"package": {
"name": "github.com/crossplane/crossplane/v2",
"purl": "pkg:golang/github.com/crossplane/crossplane/v2",
"ecosystem": "Go"
},
"database_specific": {
"source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-wfqx-gjrf-g28r/GHSA-wfqx-gjrf-g28r.json",
"last_known_affected_version_range": "<= 2.2.2"
}
},
{
"ranges": [
{
"type": "SEMVER",
"events": [
{
"introduced": "0"
},
{
"last_affected": "1.21.0-rc.0"
}
]
}
],
"package": {
"name": "github.com/crossplane/crossplane",
"purl": "pkg:golang/github.com/crossplane/crossplane",
"ecosystem": "Go"
},
"database_specific": {
"source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-wfqx-gjrf-g28r/GHSA-wfqx-gjrf-g28r.json"
}
}
]Publisher severity
critical
Source reference: /database_specific/severity
- Event
- #31359 · Revision 1
- Added to Heist Feed
- Publisher date