Security Digest · Vulnerability record
CVE-2025-27520: BentoML Allows Remote Code Execution (RCE) via Insecure Deserialization
BentoML is a Python library for building online serving systems optimized for AI apps and model inference.
CVSS 9.8 Critical EPSS 40.6% · p99
Should you act?
High exploit likelihood
EPSS ranks it in the top 5% of all CVEs for likely exploitation in the next 30 days. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 40.6%, percentile 99: FIRST’s model estimates a 40.6% chance of exploitation activity in the next 30 days, higher than 99% of all scored CVEs (very high). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes
bentoml(PyPI) >= 1.3.4, < 1.4.3, fixed in 1.4.3. Check your lockfile, including transitive dependencies.
What it is
BentoML is a Python library for building online serving systems optimized for AI apps and model inference. A Remote Code Execution (RCE) vulnerability caused by insecure deserialization has been identified in the latest version (v1.4.2) of BentoML. It allows any unauthenticated user to execute arbitrary code on the server. It exists an unsafe code segment in serde.py. This vulnerability is fixed in 1.4.3.
From the GitHub advisory
Summary A Remote Code Execution (RCE) vulnerability caused by insecure deserialization has been identified in the latest version(v1.4.2) of BentoML. It allows any unauthenticated user to execute arbitrary code on the server.
Details It exists an unsafe code segment in serde.py:
Through data flow analysis, it is confirmed that the payload content is sourced from an HTTP request, which can be fully manipulated by the attack. Due to the lack of validation in the code, maliciously crafted serialized data can execute harmful actions during deserialization.
PoC Environment:
- Server host: - IP: 10.98.36.123 - OS: Ubuntu - Attack host: - IP: 10.98.36.121 - OS: Ubuntu
Weakness type: CWE-502.
Product: bentoml (PyPI) · Assigned by: GitHub_M · Published: 2025-04-04
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| PyPI | bentoml | >= 1.3.4, < 1.4.3 | 1.4.3 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| bentoml | BentoML | >= 1.3.4, < 1.4.3 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 3.1 | 9.8 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| GitHub | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc, automatable yes, technical impact total.
- FIRST EPSS (model of 2026-10-21): 40.62% probability of exploitation activity in the next 30 days; percentile 99.
Timeline
- — CVE record last updated
- — CVE record published by GitHub_M
- — GitHub-reviewed advisory GHSA-33xw-247w-6hmc published (critical)
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-33xw-247w-6hmc github.com
- CVE.org record CVE-2025-27520 cve.org
- NVD entry CVE-2025-27520 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- github.com github.com