Cesanta Mongoose up to 7.20 TLS 1.3 mongoose.c mg_tls_recv_cert pubkey heap-based overflow

Summaryinfo

A vulnerability identified as critical has been detected in Cesanta Mongoose up to 7.20. This impacts the function mg_tls_recv_cert of the file mongoose.c of the component TLS 1.3 Handler. Performing a manipulation of the argument pubkey results in heap-based overflow. This vulnerability is known as CVE-2026-5244. Remote exploitation of the attack is possible. Furthermore, an exploit is available. You should upgrade the affected component. The vendor was contacted early, responded in a very professional manner and quickly released a fixed version of the affected product.

Detailsinfo

A vulnerability classified as critical has been found in Cesanta Mongoose up to 7.20. This affects the function mg_tls_recv_cert of the file mongoose.c of the component TLS 1.3 Handler. The manipulation of the argument pubkey with an unknown input leads to a heap-based overflow vulnerability. CWE is classifying the issue as 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(). This is going to have an impact on confidentiality, integrity, and availability.

This vulnerability is uniquely identified as CVE-2026-5244. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details and a public exploit are known.

It is declared as proof-of-concept. The vendor was contacted early, responded in a very professional manner and quickly released a fixed version of the affected product.

Upgrading to version 7.21 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch 0d882f1b43ff2308b7486a56a9d60cd6dba8a3f1 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

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

Productinfo

Vendor

• Cesanta

Name

• Mongoose

Version

• 7.0
• 7.1
• 7.2
• 7.3
• 7.4
• 7.5
• 7.6
• 7.7
• 7.8
• 7.9
• 7.10
• 7.11
• 7.12
• 7.13
• 7.14
• 7.15
• 7.16
• 7.17
• 7.18
• 7.19
• 7.20

License

• open-source

Website

• Product: https://github.com/cesanta/mongoose/

CPE 2.3info

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CPE 2.2info

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Entryinfo

Submitinfo

Accepted

• Submit #770063: Cesanta Mongoose 7.20 Heap-based Buffer Overflow (by the_evilsocket)

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

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