GHSA-9wj4-8h85-pgrw CVE-2025-48879 PYSEC-2026-1713
OctoPrint Vulnerable to Denial of Service through malformed HTTP request in OctoPrint
- Severity
- 6.5 / 10
- Medium · CVSS 3.1
- Exploit chance (EPSS)
- 0.26%
- Chance of exploitation in the next 30 days. Higher than 17.28% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-140 Improper Neutralization of Delimiters
- CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop')
- Fix
1.11.2- Upgrade octoprint to this version or later
Description
Impact
OctoPrint versions up until and including 1.11.1 contain a vulnerability that allows any unauthenticated attacker to send a manipulated broken multipart/form-data request to OctoPrint and through that make the web server component become unresponsive. This could be used to effectively run a denial of service attack on the OctoPrint server.
Patches
The vulnerability has been patched in version 1.11.2.
Workaround
OctoPrint administrators are once more reminded to not make OctoPrint available on hostile networks (e.g. the internet), regardless of whether this vulnerability is patched or not.
Details
The issue can be triggered by a broken multipart/form-data request lacking an end boundary to any of OctoPrint's endpoints implemented through the octoprint.server.util.tornado.UploadStorageFallbackHandler request handler. The request handler will get stuck in an endless busy loop, looking for a part of the request that will never come. As Tornado is single-threaded, that will effectively block the whole web server.
The fix adds detection of invalid requests like that and ensures they are handled gracefully with an HTTP 400 Bad Request response.
Credits
This vulnerability was discovered and responsibly disclosed to OctoPrint by Jacopo Tediosi.
Affected versions
PyPI
| Package | Vulnerable | Fixed in |
|---|---|---|
| octoprint | < 1.11.2 |
1.11.2 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
octoprint PyPI → 1.11.2
- pip
pip install --upgrade "octoprint>=1.11.2"- poetry
poetry add "octoprint>=1.11.2"- uv
uv add "octoprint>=1.11.2"
Severity breakdown
CVSS 3.1 6.5
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Attack vector
- Adjacent
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Weakness
CWE-140: Improper Neutralization of Delimiters
The product does not neutralize or incorrectly neutralizes delimiters.
How to prevent it
- Implementation: Developers should anticipate that delimiters will be injected/removed/manipulated in the input vectors of their product. Use an appropriate combination of denylists and allowlists to ensure only valid, expected and appropriate input is processed by the system.
- Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
- Implementation: While it is risky to use dynamically-generated query strings, code, or commands that mix control and data together, sometimes it may be unavoidable. Properly quote arguments and escape any special characters within those arguments. The most conservative approach is to escape or filter all characters that do not pass an extremely strict allowlist (such as everything that is not alphanumeric or white space). If some special characters are still needed, such as white space, wrap each argument in quotes after the escaping/filtering step. Be careful of argument injection (CWE-88).
- Implementation: Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.
CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')
The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-j4h9-pm27-4rfw OctoPrint has possible file exfiltration via query parameters on upload endpoints | High | Also affects octoprint |
| GHSA-p6qx-ghxm-389h OctoPrint has XSS in its Suppressed Command Notifications | Medium | Also affects octoprint |
| GHSA-xg4x-w2j3-57h6 OctoPrint has Timing Side-Channel Vulnerability in API Key Authentication | Medium | Also affects octoprint |
| GHSA-crvm-xjhm-9h29 OctoPrint vulnerable to XSS in Action Commands Notification and Prompt | Medium | Also affects octoprint |
| GHSA-49mj-x8jp-qvfc OctoPrint is Vulnerable to RCE Attacks via Unsanitized Filename in File Upload | High | Also affects octoprint |
| GHSA-m9jh-jf9h-x3h2 OctoPrint vulnerable to possible file extraction via upload endpoints | Medium | Also affects octoprint |
| GHSA-qw93-h6pf-226x OctoPrint Authenticated Reverse Proxy Page Authentication Bypass | Medium | Also affects octoprint |
| GHSA-cc6x-8cc7-9953 OctoPrint has API key access in settings without reauthentication | Medium | Also affects octoprint |
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