Description

Unbounded Arch package file metadata can cause resource amplification in Gitea package uploads

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "4.3",
  "pubDate": "2026-08-13T17:17:30.360Z",
  "pubdate": "2026-08-13T17:17:30.360Z",
  "executiveSummary": "A resource amplification vulnerability exists in Gitea related to the handling of Arch package file metadata during package uploads. This vulnerability type involves improper resource consumption management, which can lead to denial of service conditions through excessive resource exhaustion.\nThe affected product is Gitea, specifically within its package registry implementation handling Arch Linux package formats. Successful exploitation allows an authenticated or unauthenticated threat actor, depending on registry configuration, to submit maliciously crafted package metadata designed to trigger disproportionate memory or CPU consumption on the server.\nThe primary risk implication is service degradation or complete availability loss of the Gitea instance due to resource starvation. The attacker capability centers on inducing server-side resource exhaustion via the package upload mechanism without requiring complex interaction, potentially impacting all tenants and services hosted on the affected Gitea instance.",
  "technicalDetails": "The root cause of the vulnerability stems from the absence of strict size limitations, validation checks, or parsing constraints on Arch package file metadata during the ingestion phase of package uploads within the Gitea package registry component.\nWhen a client uploads an Arch package, the Gitea server processes the associated metadata files (such as PKGINFO or .BUILDINFO equivalents). If these metadata structures contain unbounded fields or maliciously structured recursive elements, the parsing logic consumes excessive system memory and CPU cycles.\nThe attack flow begins with the threat actor crafting a specialized Arch package containing hypertrophied or structurally anomalous metadata. The attacker then initiates a package upload request targeting the Gitea package upload endpoint.\nUpon receiving the upload payload, the vulnerable component parses the unbounded package file metadata without enforcing adequate resource limits. This triggers memory exhaustion or CPU pinning on the host running the Gitea service.\nDepending on the specific Gitea instance configuration, network exposure is present wherever the package registry feature is enabled and accessible to users permitted to upload packages. Privilege and authentication requirements typically align with the access controls enforced by the specific package registry scope, though misconfigured instances may permit anonymous or low-privileged uploads.\nThe payload behavior focuses entirely on amplification, turning a small upload request into a massive computational or memory allocation task on the server. The post-exploitation impact is characterized by application instability, unresponsiveness, or fatal out-of-memory crashes affecting the entire Gitea service."
}