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Not in CISA KEV
HIGH severity

CVE-2024-10907 — fschat

HIGH

CVE-2024-10907 is a high-severity (CVSS 7.5) CWE-835 vulnerability in fschat. The records list no fixed version yet; check the vendor advisory below and apply the mitigations in the meantime.

FastChat Uncontrolled Resource Consumption vulnerability

Also known asPYSEC-2026-1398
Published
Updated
Affected
1 pkg
Patched
See advisory
Exploits
None indexed
Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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.

Exploitation and automatability from CISA’s SSVC triage for CVE-2024-10907.

EPSS Exploitation Probability

via FIRST.org ↗
0.7%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs54th percentile — riskier than 54% of all scored CVEsHighest risk
0.00%0.47%0.93%1.40%0.9%0.7%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected
🐍fschat

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

In lm-sys/fastchat Release v0.2.36, the server fails to handle excessive characters appended to the end of multipart boundaries. This flaw can be exploited by sending malformed multipart requests with arbitrary characters at the end of the boundary. Each extra character is processed in an infinite loop, leading to excessive resource consumption and a complete denial of service (DoS) for all users. The vulnerability is unauthenticated, meaning no user login or interaction is required for an attacker to exploit this issue.

Affected Packages

1 total
EcosystemPackageVulnerable rangeFix
🐍PyPIfschatall versionsNo fix

Affected Products

1 product · 1 configurations
Application
fastchatlm-sys
1 version
0.2.36

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for fschat, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Remediation status

    The records we use list no patched version of fschat for CVE-2024-10907. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.

  3. Mitigate without a patch

    Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

In lm-sys/fastchat Release v0.2.36, the server fails to handle excessive characters appended to the end of multipart boundaries. This flaw can be exploited by sending malformed multipart requests with arbitrary characters at the end of the boundary. Each extra character is processed in an infinite loop, leading to excessive resource consumption and a complete denial of service (DoS) for all users. The vulnerability is unauthenticated, meaning no user login or interaction is required for an attacker to exploit this issue.
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CVE-2024-10907: fschat DoS (High 7.5)