snap7 1.4.3 /core/s7_server.cpp PerformFunctionWrite heap-based overflow

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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4.2$0-$5k0.00

Summaryinfo

A vulnerability has been found in snap7 1.4.3 and classified as critical. The impacted element is the function TS7Worker::PerformFunctionWrite of the file /core/s7_server.cpp. This manipulation causes heap-based overflow. This vulnerability is registered as CVE-2026-51218. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability has been found in snap7 1.4.3 and classified as critical. Affected by this vulnerability is the function TS7Worker::PerformFunctionWrite of the file /core/s7_server.cpp. The manipulation with an unknown input leads to a heap-based overflow vulnerability. The CWE definition for the vulnerability is CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). As an impact it is known to affect availability. The summary by CVE is:

A heap buffer overflow in the TS7Worker::PerformFunctionWrite() function (/core/s7_server.cpp) of snap7 v1.4.3 allows attackers to cause a Denial of Service (DoS) via a crafted packet.

This vulnerability is known as CVE-2026-51218 since 06/07/2026. The exploitation appears to be easy. The attack can be launched remotely. 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 06/30/2026).

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

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.3
VulDB Meta Temp Score: 4.2

VulDB Base Score: 4.3
VulDB Temp Score: 4.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Heap-based overflow
CWE: CWE-122 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

06/07/2026 CVE reserved
06/29/2026 +22 days VulDB entry created
06/30/2026 +0 days Advisory disclosed
06/30/2026 +0 days VulDB entry last update

Sourcesinfo

Status: Not defined

CVE: CVE-2026-51218 (🔒)
GCVE (CVE): GCVE-0-2026-51218
GCVE (VulDB): GCVE-100-374755

Entryinfo

Created: 06/30/2026 01:13
Changes: 06/30/2026 01:13 (52)
Complete: 🔍
Cache ID: 216::103

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

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