EUVD-2026-18184
GHSA-hm7q-jq63-pr78
Severity by source
CVSS:4.0/AV:N/AC:H/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
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
CVSS:4.0/AV:N/AC:H/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
Lifecycle Timeline
6DescriptionCVE.org
A vulnerability was determined in Cesanta Mongoose up to 7.20. Affected is the function mg_tls_verify_cert_signature of the file mongoose.c of the component P-384 Public Key Handler. Executing a manipulation can lead to authorization bypass. The attack can be executed remotely. Attacks of this nature are highly complex. The exploitability is told to be difficult. The exploit has been publicly disclosed and may be utilized. Upgrading to version 7.21 is able to address this issue. This patch is called 0d882f1b43ff2308b7486a56a9d60cd6dba8a3f1. The affected component should be upgraded. The vendor was contacted early, responded in a very professional manner and quickly released a fixed version of the affected product.
AnalysisAI
Authorization bypass in Cesanta Mongoose up to version 7.20 allows remote, unauthenticated attackers to bypass TLS certificate signature verification in the P-384 public key handler (mg_tls_verify_cert_signature function in mongoose.c), potentially enabling man-in-the-middle attacks or unauthorized access. The attack is highly complex (CVSS AC:H) but publicly disclosed exploit code exists, with vendor-released patch available in version 7.21.
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Vulnerability AssessmentAI
| Risk Assessment | The CVSS score of 5.6 (Medium) with vector AV:N/AC:H/PR:N/UI:N indicates remote, unauthenticated exploitation with high attack complexity and partial impact on confidentiality, integrity, and availability. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker intercepts TLS traffic to a Mongoose-based embedded device or server (e.g., IoT device, firmware update server, or embedded web interface). By exploiting the P-384 signature verification bypass, the attacker crafts a malicious certificate with an invalid signature that passes Mongoose's flawed validation logic, establishing a successful man-in-the-middle position. … |
| Remediation | Vendor-released patch: Upgrade to Cesanta Mongoose version 7.21 or later, which includes the fix commit 0d882f1b43ff2308b7486a56a9d60cd6dba8a3f1. … Detailed patch versions, workarounds, and compensating controls in full report. |
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External POC / Exploit Code
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