CVE-2026-73555Network attack vector

Unauthenticated internal path disclosure via validation errors

Published Aug 13, 2026 · Updated Aug 13, 2026

Information disclosure in vLLM before 0.26.0 allows remote attackers to read internal server details through malformed JSON requests. The validation_exception_handler stringifies FastAPI RequestValidationError objects, while sanitize_message leaves traceback-style paths intact in responses. Unauthenticated access to JSON POST endpoints is sufficient to reveal the OS username, Python and virtual-environment paths, package structure, line numbers, and handler names, but not file contents.

CVSS severity5.3
Medium
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Information disclosure in vLLM before 0.26.0 allows remote attackers to read internal server details through malformed JSON requests. The validation_exception_handler stringifies FastAPI RequestValidationError objects, while sanitize_message leaves traceback-style paths intact in responses. Unauthenticated access to JSON POST endpoints is sufficient to reveal the OS username, Python and virtual-environment paths, package structure, line numbers, and handler names, but not file contents.

The record

CVE
CVE-2026-73555
Published
Aug 13, 2026
Updated
Aug 13, 2026
Vendor
vLLM Project
Product
vLLM
Classifications
CWE-209, T1592.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 13, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.26.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

vLLM Project · vLLMversion=< 0.26.0

Published CVSS scores

5.3Red HatCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
5.3GitHub CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-209Generation of Error Message Containing Sensitive Information
T1592.002Gather Victim Host Information: Software

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo