CVE-2026-73260

Status: DeferredHigh (7.5)—

Severity7.5High · CVSS 3.1

Exploitation probability0.23 %higher than 13% of CVEs

Active exploitationNonot in the CISA catalog

Public exploitNot knownno public code found

Mongoose is an embedded web server and network library. Prior to 7.23, the built-in TLS certificate parser selected by MG_TLS_BUILTIN fails to verify that a long-form DER element length fits within the remaining certificate buffer. In mg_der_to_tlv() and mg_der_next(), a peer-controlled length can advance the parser beyond the certificate and underflow the remaining uint32_t length, causing mg_tls_parse_cert_der() to continue walking an invalid pointer. An unauthenticated malicious TLS server, or a client presenting a certificate to a server configured for client certificates, can trigger an out-of-bounds read and denial of service during the handshake. This issue is fixed in version 7.23.

CVSS

Base score: 7.5
Version: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 0.23 %
Percentile among all scored CVEs: 13
Score date: 10/20/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

ExploitationT1190 Exploit Public-Facing Applicationinitial access95 %
Primary impactT1499.004 Application or System Exploitationimpact85 %

Vector AV:N/PR:N/UI:N y el texto indica lectura fuera de límites y denegación de servicio durante el handshake TLS por un servidor o cliente malicioso.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

ATT&CK mitigations that cover these techniques

Filter Network Traffic Vulnerability Scanning Privileged Account Management Network Segmentation Limit Access to Resource Over Network Application Isolation and Sandboxing

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Cesanta — Mongoose^AI

CWEs

CWE-125

References

Show 3 references

Raw JSON (NVD)

Show

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  "id": "CVE-2026-73260",
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  "metrics": {
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          "role": "CISA Coordinator",
          "options": [
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          "version": "2.0.3",
          "timestamp": "2026-10-20T01:49:51.017897Z"
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          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
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        "exploitabilityScore": 3.9
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  "published": "2026-10-14T19:17:19.840",
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      "url": "https://github.com/cesanta/mongoose/commit/a8b4ae95db3c2db85e5ad9db3fefaeebb5f7b43e",
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  "lastModified": "2026-10-20T02:17:11.720",
  "sourceIdentifier": "security-advisories@github.com"
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