davenardella snap7 up to 1.4.3 s7_micro_client.cpp opUpload DataLen memory corruption

CVSS Meta Temp Score
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CTI Interest Score
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5.6$0-$5k0.00

Summaryinfo

A vulnerability classified as problematic has been found in davenardella snap7 up to 1.4.3. The impacted element is the function TSnap7MicroClient::opUpload of the file src/core/s7_micro_client.cpp. The manipulation of the argument DataLen leads to memory corruption. This vulnerability is uniquely identified as CVE-2026-90572. The attack is possible to be carried out remotely. Moreover, an exploit is present. The project was informed of the problem early through an issue report but has not responded yet.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in davenardella snap7 up to 1.4.3. This issue affects the function TSnap7MicroClient::opUpload of the file src/core/s7_micro_client.cpp. The manipulation of the argument DataLen with an unknown input leads to a memory corruption vulnerability. Using CWE to declare the problem leads to CWE-119. The product performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer. Impacted is confidentiality, integrity, and availability.

The weakness was disclosed 08/01/2026 by Mayur Agnihotri (Mayur021) as 30. The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-90572. The exploitation is known to be easy. The attack may be initiated remotely. Additional levels of successful authentication are required for exploitation. Technical details as well as a public exploit are known.

The exploit is available at github.com. It is declared as proof-of-concept. The project was informed of the problem early through an issue report but has not responded yet.

Addressing this vulnerability is possible by firewalling 102.

The vulnerability is also documented in the vulnerability database at CNNVD (CNNVD-2026-93958989). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Vendor

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 5.9
VulDB Meta Temp Score: 5.6

VulDB Base Score: 4.7
VulDB Temp Score: 4.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

Researcher Base Score: 8.2
Researcher Vector: 🔒

CNA Base Score: 4.7
CNA Vector: 🔒

CVSSv2info

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

Exploitinginfo

Class: Memory corruption
CWE: CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Access: Public
Status: Proof-of-Concept
Download: 🔒

EPSS Score: 🔒
EPSS Percentile: 🔒

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: 🔒

Firewalling: 🔒

Timelineinfo

08/01/2026 Vendor informed
08/01/2026 +0 days Advisory disclosed
09/12/2026 +42 days VulDB entry created
09/19/2026 +7 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: 30
Researcher: Mayur Agnihotri (Mayur021)
Status: Not defined

CVE: CVE-2026-90572 (🔒)
GCVE (CVE): GCVE-0-2026-90572
GCVE (VulDB): GCVE-100-403157
CNNVD: CNNVD-2026-93958989 - Dave Nardella Snap7 缓冲区错误漏洞

scip Labs: https://www.scip.ch/en/?labs.20161013

Entryinfo

Created: 09/12/2026 18:16
Updated: 09/19/2026 15:12
Changes: 09/12/2026 18:16 (58), 09/12/2026 18:55 (8), 09/12/2026 18:56 (8), 09/12/2026 18:59 (3), 09/14/2026 18:09 (6), 09/19/2026 15:12 (32)
Complete: 🔍
Submitter: mayur021
Committer: mayur021
Cache ID: 216::103

Submitinfo

Accepted

  • Submit #912711: davenardella snap7 1.4.3 Memory Corruption (by mayur021)

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Discussion

 mayur021 (+1)
20 days ago
Finder here. One clarification on the direction of this issue, since the write-up can be read the wrong way round.

TSnap7MicroClient::opUpload is client-side only. It is defined at s7_micro_client.cpp:997 and reached only from the client's own job dispatcher at 2565, through the Upload API. On the server side, TS7Worker::PerformFunctionUpload at s7_server.cpp:883 is a stub that answers Code7NeedPassword and parses no payload, commented "Upload is not implemented".

So the malicious DataLen arrives from the PLC or endpoint the client connected to. A SCADA system or HMI running snap7 is the victim here, not an exposed service being attacked. That is what makes this path distinct from the earlier snap7 entries, which are all server-side.
 mayur021 (+0)
20 days ago
Correction to my own last line. Not all the earlier snap7 findings are server-side: CVE-2026-16225 is TSnap7Peer::NegotiatePDULength, and issue 17 in the same tracker is explicitly client-side, in opWriteArea. What actually distinguishes this path is that it is the upload reassembly one and does not depend on PDU length negotiation, so it fires on the first upload response.

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