Linux Kernel up to 5.13.2 udf/misc.c udf_symlink null pointer dereference

CVSS Meta Temp Score
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CTI Interest Score
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5.5$0-$5k0.00

Summaryinfo

A vulnerability classified as critical has been found in Linux Kernel up to 5.13.2. Affected by this vulnerability is the function udf_symlink of the file udf/misc.c. This manipulation causes null pointer dereference. This vulnerability is registered as CVE-2021-47353. No exploit is available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 5.13.2. It has been declared as critical. Affected by this vulnerability is the function udf_symlink of the file udf/misc.c. The manipulation with an unknown input leads to a null pointer dereference vulnerability. The CWE definition for the vulnerability is CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. As an impact it is known to affect availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: udf: Fix NULL pointer dereference in udf_symlink function In function udf_symlink, epos.bh is assigned with the value returned by udf_tgetblk. The function udf_tgetblk is defined in udf/misc.c and returns the value of sb_getblk function that could be NULL. Then, epos.bh is used without any check, causing a possible NULL pointer dereference when sb_getblk fails. This fix adds a check to validate the value of epos.bh.

The advisory is shared at git.kernel.org. This vulnerability is known as CVE-2021-47353 since 05/21/2024. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 237865 (Ubuntu 16.04 LTS : Linux kernel vulnerabilities (USN-7554-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 4.4.276, 4.9.276, 4.14.240, 4.19.198, 5.4.133, 5.10.51, 5.12.18 or 5.13.3 eliminates this vulnerability. Applying the patch 2f3d9ddd32a2/371566f63cbd/baea588a42d6/3638705ecd5a/80d505aee639/21bf1414580c/aebed6b19e51/5150877e4d99/fa236c2b2d44 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (237865). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.6
VulDB Meta Temp Score: 5.5

VulDB Base Score: 5.7
VulDB Temp Score: 5.5
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔍

CVSSv2info

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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 237865
Nessus Name: Ubuntu 16.04 LTS : Linux kernel vulnerabilities (USN-7554-1)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: Kernel 4.4.276/4.9.276/4.14.240/4.19.198/5.4.133/5.10.51/5.12.18/5.13.3
Patch: 2f3d9ddd32a2/371566f63cbd/baea588a42d6/3638705ecd5a/80d505aee639/21bf1414580c/aebed6b19e51/5150877e4d99/fa236c2b2d44

Timelineinfo

05/21/2024 🔍
05/21/2024 +0 days 🔍
05/21/2024 +0 days 🔍
06/06/2025 +381 days 🔍

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2021-47353 (🔍)
GCVE (CVE): GCVE-0-2021-47353
GCVE (VulDB): GCVE-100-265705

Entryinfo

Created: 05/21/2024 20:24
Updated: 06/06/2025 16:07
Changes: 05/21/2024 20:24 (58), 12/24/2024 17:26 (12), 06/06/2025 16:07 (2)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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