vulnerability / NVI-00016153 / Revision 1
Gitea Actions Artifacts V4 signed URL HMAC ambiguity allows cross-repository artifact read and cross-task upload-state write
GitHub lists this reviewed advisory for code.gitea.io/gitea. 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.
9.6 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.
code.gitea.io/gitea
source listed>= 1.22.0, < 1.26.2
### Summary Gitea Actions Artifacts V4 signed upload/download URLs can be rewritten to access a different running task and repository context while preserving the original HMAC signature. An attacker with permission to run a Gitea Actions job can turn a signed URL for an attacker-controlled artifact into a URL that reads artifacts from another task context, or writes attacker-controlled data into another task's artifact upload staging context, including in a private repository. This is one vulnerability with two exploit paths: - `DownloadArtifact`: cross-task/cross-repository artifact read, giving `C:H`. - `UploadArtifact`: cross-task artifact staging write and metadata mutation, giving `I:H`. ### Details The root cause is that the V4 artifact signed URL signature is built from raw concatenated fields without delimiters or length-prefixing: ```go func (r *artifactV4Routes) buildSignature(endpoint, expires, artifactName string, taskID, artifactID int64) []byte { mac := hmac.New(sha256.New, setting.GetGeneralTokenSigningSecret()) mac.Write([]byte(endpoint)) mac.Write([]byte(expires)) mac.Write([]byte(artifactName)) _, _ = fmt.Fprint(mac,
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-hg5r-vq93-9fv6 ↗
GitHub Advisory Database · vendor advisory
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Public revision history
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- Revision 1 ·
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