2.5

CVSS Score

3.1

Basic Information

CVE ID

CVE-2021-29559

GHSA ID

GHSA-59q2-x2qc-4c97

EPSS Score

0.0259%

CWE

CWE-125

Published

5/21/2021

Updated

10/31/2024

KEV Status

Technology

Python

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CVE-2021-29559

CVE-2021-29559: Heap OOB access in unicode ops

Impact

An attacker can access data outside of bounds of heap allocated array in tf.raw_ops.UnicodeEncode:

import tensorflow as tf

input_values = tf.constant([58], shape=[1], dtype=tf.int32)
input_splits = tf.constant([[81, 101, 0]], shape=[3], dtype=tf.int32)
output_encoding = "UTF-8"

tf.raw_ops.UnicodeEncode(
    input_values=input_values, input_splits=input_splits,
    output_encoding=output_encoding)

This is because the implementation assumes that the input_value/input_splits pair specify a valid sparse tensor.

Patches

We have patched the issue in GitHub commit 51300ba1cc2f487aefec6e6631fef03b0e08b298.

The fix will be included in TensorFlow 2.5.0. We will also cherrypick this commit on TensorFlow 2.4.2, TensorFlow 2.3.3, TensorFlow 2.2.3 and TensorFlow 2.1.4, as these are also affected and still in supported range.

For more information

Please consult our security guide for more information regarding the security model and how to contact us with issues and questions.

Attribution

This vulnerability has been reported by Ying Wang and Yakun Zhang of Baidu X-Team.

(GitHub Advisory)

2.5

CVSS Score

3.1

Basic Information

CVE ID

CVE-2021-29559

GHSA ID

GHSA-59q2-x2qc-4c97

EPSS Score

0.0259%

CWE

CWE-125

Published

5/21/2021

Updated

10/31/2024

KEV Status

Technology

Python

Technical Details

CVSS Vector

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L

Package Name	Ecosystem	Vulnerable Versions	First Patched Version
tensorflow	pip	< 2.1.4	2.1.4
tensorflow	pip	>= 2.2.0, < 2.2.3	2.2.3
tensorflow	pip	>= 2.3.0, < 2.3.3	2.3.3
tensorflow	pip	>= 2.4.0, < 2.4.2	2.4.2
tensorflow-cpu	pip	< 2.1.4	2.1.4
tensorflow-cpu	pip	>= 2.2.0, < 2.2.3	2.2.3
tensorflow-cpu	pip	>= 2.3.0, < 2.3.3	2.3.3
tensorflow-cpu	pip	>= 2.4.0, < 2.4.2	2.4.2
tensorflow-gpu	pip	< 2.1.4	2.1.4
tensorflow-gpu	pip	>= 2.2.0, < 2.2.3	2.2.3
tensorflow-gpu	pip	>= 2.3.0, < 2.3.3	2.3.3
tensorflow-gpu	pip	>= 2.4.0, < 2.4.2	2.4.2

Vulnerability Intelligence
Miggo AI

Root Cause Analysis

The vulnerability stems from the UnicodeEncodeOp::Compute function's failure to validate input_splits parameters. The commit diff shows critical validation logic was added to this function (OP_REQUIRES checks for split boundaries and ordering). The original code processed input_splits without these safeguards, allowing attackers to craft malicious split/values pairs that access memory beyond the allocated buffer. The direct correlation between the vulnerability description, CWE-125 classification, and the patched code location confirms this function's role.

Vulnerable functions

Only Mi**o us*rs **n s** t*is s**tion

WAF Protection Rules

WAF Rule

### Imp**t *n *tt**k*r **n ****ss **t* outsi** o* *oun*s o* ***p *llo**t** *rr*y in `t*.r*w_ops.Uni*o***n*o**`: ```pyt*on import t*nsor*low *s t* input_v*lu*s = t*.*onst*nt([**], s**p*=[*], *typ*=t*.int**) input_splits = t*.*onst*nt([[**, ***, *]],

Reasoning

T** vuln*r**ility st*ms *rom t** Uni*o***n*o**Op::*omput* *un*tion's **ilur* to v*li**t* input_splits p*r*m*t*rs. T** *ommit *i** s*ows *riti**l v*li**tion lo*i* w*s ***** to t*is *un*tion (OP_R*QUIR*S ****ks *or split *oun**ri*s *n* or**rin*). T** o

2.5

Basic Information

Concerned about an active attack path?

CVE-2021-29559: Heap OOB access in unicode ops

Impact

Patches

For more information

Attribution

2.5

Basic Information

Technical Details

Vulnerability IntelligenceMiggo AI

Root Cause Analysis

Vulnerable functions

WAF Protection Rules

WAF Rule

Reasoning

Vulnerability Intelligence
Miggo AI