CVE-2026-5244
Cesanta Mongoose TLS 1.3 mongoose.c mg_tls_recv_cert heap-based overflow
Description
A vulnerability 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. Such manipulation of the argument pubkey leads to heap-based buffer overflow. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. Upgrading to version 7.21 mitigates this issue. The name of the patch is 0d882f1b43ff2308b7486a56a9d60cd6dba8a3f1. It is advisable to 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.
INFO
Published Date :
April 2, 2026, 8:16 a.m.
Last Modified :
April 29, 2026, 9:46 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 2.0 | HIGH | [email protected] | ||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 3.1 | CRITICAL | [email protected] | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Upgrade Cesanta Mongoose to version 7.21.
- Apply the provided patch.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-5244.
| URL | Resource |
|---|---|
| https://github.com/cesanta/mongoose/ | Product |
| https://github.com/cesanta/mongoose/commit/0d882f1b43ff2308b7486a56a9d60cd6dba8a3f1 | Patch |
| https://github.com/cesanta/mongoose/releases/tag/7.21 | Product Release Notes |
| https://vuldb.com/submit/770063 | Exploit Third Party Advisory VDB Entry |
| https://vuldb.com/vuln/354825 | Third Party Advisory VDB Entry |
| https://vuldb.com/vuln/354825/cti | Permissions Required VDB Entry |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-5244 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-5244
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-5244 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-5244 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Apr. 29, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Added CPE Configuration OR *cpe:2.3:a:cesanta:mongoose:*:*:*:*:*:*:*:* versions from (including) 7.0 up to (excluding) 7.21 Added Reference Type VulDB: https://github.com/cesanta/mongoose/ Types: Product Added Reference Type VulDB: https://github.com/cesanta/mongoose/commit/0d882f1b43ff2308b7486a56a9d60cd6dba8a3f1 Types: Patch Added Reference Type VulDB: https://github.com/cesanta/mongoose/releases/tag/7.21 Types: Product, Release Notes Added Reference Type VulDB: https://vuldb.com/submit/770063 Types: Exploit, Third Party Advisory, VDB Entry Added Reference Type VulDB: https://vuldb.com/vuln/354825 Types: Third Party Advisory, VDB Entry Added Reference Type VulDB: https://vuldb.com/vuln/354825/cti Types: Permissions Required, VDB Entry -
Data Remediation by [email protected]
Apr. 29, 2026
Action Type Old Value New Value Changed CVSS V4.0 Score 6.9 5.5 -
New CVE Received by [email protected]
Apr. 02, 2026
Action Type Old Value New Value Added Description A vulnerability 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. Such manipulation of the argument pubkey leads to heap-based buffer overflow. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. Upgrading to version 7.21 mitigates this issue. The name of the patch is 0d882f1b43ff2308b7486a56a9d60cd6dba8a3f1. It is advisable to 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. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L Added CVSS V2 (AV:N/AC:L/Au:N/C:P/I:P/A:P) Added CWE CWE-119 Added CWE CWE-122 Added Reference https://github.com/cesanta/mongoose/ Added Reference https://github.com/cesanta/mongoose/commit/0d882f1b43ff2308b7486a56a9d60cd6dba8a3f1 Added Reference https://github.com/cesanta/mongoose/releases/tag/7.21 Added Reference https://vuldb.com/submit/770063 Added Reference https://vuldb.com/vuln/354825 Added Reference https://vuldb.com/vuln/354825/cti