NASM 2.15rc0 asm File stdscan.c scan buffer overflow

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
4.9$0-$5k0.00

Summaryinfo

A vulnerability identified as critical has been detected in NASM 2.15rc0. The affected element is the function scan of the file stdscan.c of the component asm File Handler. Performing a manipulation results in buffer overflow. This vulnerability is identified as CVE-2020-21687. The attack can be initiated remotely. There is not any exploit available. Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Detailsinfo

A vulnerability classified as critical has been found in NASM 2.15rc0 (Programming Tool Software). This affects the function scan of the file stdscan.c of the component asm File Handler. The manipulation with an unknown input leads to a buffer overflow vulnerability. CWE is classifying the issue as CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. This is going to have an impact on availability. The summary by CVE is:

Buffer Overflow vulnerability in scan function in stdscan.c in nasm 2.15rc0 allows remote attackers to cause a denial of service via crafted asm file.

The weakness was released 08/23/2023. It is possible to read the advisory at bugzilla.nasm.us. This vulnerability is uniquely identified as CVE-2020-21687 since 08/13/2020. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/16/2023).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.9
VulDB Meta Temp Score: 4.9

VulDB Base Score: 4.3
VulDB Temp Score: 4.3
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔍

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

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

Exploitinginfo

Class: Buffer overflow
CWE: CWE-120 / CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔍

Timelineinfo

08/13/2020 🔍
08/23/2023 +1105 days 🔍
08/23/2023 +0 days 🔍
09/16/2023 +24 days 🔍

Sourcesinfo

Advisory: bugzilla.nasm.us
Status: Confirmed

CVE: CVE-2020-21687 (🔍)
GCVE (CVE): GCVE-0-2020-21687
GCVE (VulDB): GCVE-100-237771

Entryinfo

Created: 08/23/2023 10:16 AM
Updated: 09/16/2023 07:49 AM
Changes: 08/23/2023 10:16 AM (40), 09/16/2023 07:49 AM (11)
Complete: 🔍
Cache ID: 244:AF4:40

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Do you want to use VulDB in your project?

Use the official API to access entries easily!