CVE-2026-25242 — gogs
Fix: gogs/gogs@628216dCVE-2026-25242 is a security vulnerability in gogs.io/gogs. A fix is available for gogs.io/gogs — see the affected versions and patch details below.
Gogs allows unauthenticated file uploads
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-25242.
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.
Real-World Exposure
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 | 0.14.1go get gogs.io/gogs@v0.14.1 |
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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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 CVE-2026-25242 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-25242 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-25242. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-25242 in your dependencies?
O3 Security finds CVE-2026-25242 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.