CVE-2021-37646

Bad alloc in `StringNGrams` caused by integer conversion in TensorFlow

Severity Score

5.5

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

TensorFlow is an end-to-end open source platform for machine learning. In affected versions the implementation of `tf.raw_ops.StringNGrams` is vulnerable to an integer overflow issue caused by converting a signed integer value to an unsigned one and then allocating memory based on this value. The [implementation](https://github.com/tensorflow/tensorflow/blob/8d72537c6abf5a44103b57b9c2e22c14f5f49698/tensorflow/core/kernels/string_ngrams_op.cc#L184) calls `reserve` on a `tstring` with a value that sometimes can be negative if user supplies negative `ngram_widths`. The `reserve` method calls `TF_TString_Reserve` which has an `unsigned long` argument for the size of the buffer. Hence, the implicit conversion transforms the negative value to a large integer. We have patched the issue in GitHub commit c283e542a3f422420cfdb332414543b62fc4e4a5. The fix will be included in TensorFlow 2.6.0. We will also cherrypick this commit on TensorFlow 2.5.1, TensorFlow 2.4.3, and TensorFlow 2.3.4, as these are also affected and still in supported range.

TensorFlow es una plataforma de código abierto de extremo a extremo para el aprendizaje automático. En las versiones afectadas, la implementación "tf.raw_ops.StringNGrams" es vulnerable a un problema de desbordamiento de enteros causado al convertir un valor entero con signo a uno sin signo y la posterior asignación de memoria basada en este valor. La [implementación](https://github.com/tensorflow/tensorflow/blob/8d72537c6abf5a44103b57b9c2e22c14f5f49698/tensorflow/core/kernels/string_ngrams_op.cc#L184) llama a "reserve" en una "tstring" con un valor que a veces puede ser negativo si el usuario proporciona "ngram_widths" negativo. El método "reserve" llama a "TF_TString_Reserve" que presenta un argumento "unsigned long" para el tamaño del buffer. Por lo tanto, la conversión implícita transforma el valor negativo en un entero grande. Hemos parcheado el problema en el commit de GitHub c283e542a3f422420cfdb332414543b62fc4e4a5. La corrección será incluida en TensorFlow versión 2.6.0. También seleccionaremos este commit en TensorFlow versión 2.5.1, TensorFlow versión 2.4.3, y TensorFlow versión 2.3.4, ya que estos también están afectados y todavía en el rango de soporte.

*Credits: N/A

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Attack Vector

Local

Attack Complexity

Low

Authentication

None

Confidentiality

None

Integrity

None

Availability

Partial

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2021-07-29 CVE Reserved
2021-08-12 CVE Published
2023-03-08 EPSS Updated
2024-08-04 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-681: Incorrect Conversion between Numeric Types

CAPEC

References (2)

URL	Tag	Source
https://github.com/tensorflow/tensorflow/security/advisories/GHSA-h6jh-7gv5-28vg	Third Party Advisory

URL	Date	SRC

URL	Date	SRC
https://github.com/tensorflow/tensorflow/commit/c283e542a3f422420cfdb332414543b62fc4e4a5	2021-08-18

URL	Date	SRC

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Google Search vendor "Google"		Tensorflow Search vendor "Google" for product "Tensorflow"				>= 2.3.0 < 2.3.4 Search vendor "Google" for product "Tensorflow" and version " >= 2.3.0 < 2.3.4"		-		Affected
Google Search vendor "Google"		Tensorflow Search vendor "Google" for product "Tensorflow"				>= 2.4.0 < 2.4.3 Search vendor "Google" for product "Tensorflow" and version " >= 2.4.0 < 2.4.3"		-		Affected
Google Search vendor "Google"		Tensorflow Search vendor "Google" for product "Tensorflow"				2.5.0 Search vendor "Google" for product "Tensorflow" and version "2.5.0"		-		Affected
Google Search vendor "Google"		Tensorflow Search vendor "Google" for product "Tensorflow"				2.6.0 Search vendor "Google" for product "Tensorflow" and version "2.6.0"		rc0		Affected
Google Search vendor "Google"		Tensorflow Search vendor "Google" for product "Tensorflow"				2.6.0 Search vendor "Google" for product "Tensorflow" and version "2.6.0"		rc1		Affected
Google Search vendor "Google"		Tensorflow Search vendor "Google" for product "Tensorflow"				2.6.0 Search vendor "Google" for product "Tensorflow" and version "2.6.0"		rc2		Affected