CVE-2021-41213Public exploit

Model-execution hang via non-reentrant recursive function lock

Published Nov 5, 2021 · Updated Aug 4, 2024

Denial of service in Google TensorFlow before 2.4.4, 2.5.0 through 2.5.1, and 2.6.0 allows context-dependent attackers to hang model execution. Function wrappers in tensorflow/python/eager/def_function.py and function.py reacquire a non-reentrant threading.Lock when decorated functions recurse. A user must load an attacker-influenced model containing mutually recursive decorated functions and invoke one, leaving the executing process hung.

CVSS severity5.5
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Google TensorFlow before 2.4.4, 2.5.0 through 2.5.1, and 2.6.0 allows context-dependent attackers to hang model execution. Function wrappers in tensorflow/python/eager/def_function.py and function.py reacquire a non-reentrant threading.Lock when decorated functions recurse. A user must load an attacker-influenced model containing mutually recursive decorated functions and invoke one, leaving the executing process hung.

The record

CVE
CVE-2021-41213
Published
Nov 5, 2021
Updated
Aug 4, 2024
Vendor
Google
Product
TensorFlow
Classifications
CWE-667, CWE-662, T1499.004
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Nov 5, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=< 2.4.4
  2. Affected versionversion=>= 2.5.0, < 2.5.2
  3. Affected versionversion=>= 2.6.0, < 2.6.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

Google · TensorFlowversion=< 2.4.4; version=>= 2.5.0, < 2.5.2; version=>= 2.6.0, < 2.6.1

Published CVSS scores

5.5GitHub, Inc.CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:N/A:P
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

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.

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No observations available

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

Weakness, pattern, technique

CWE-667Improper Locking
CWE-662Improper Synchronization
T1499.004Application or System Exploitation

Public exploit references

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

Technologies

Your stack

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Your stack

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