CVE-2026-73260Public exploitNetwork attack vectorHinoki check available

Unauthenticated crashes via unchecked DER lengths

Published Oct 14, 2026 · Updated Oct 14, 2026

Out-of-bounds reads in Cesanta Mongoose before 7.23 allow remote attackers to crash built-in TLS applications via crafted certificates. mg_der_to_tlv() accepts long-form lengths exceeding the certificate buffer, causing mg_der_next() to underflow its remaining-length counter and mg_tls_parse_cert_der() to walk an invalid pointer. Exposure requires MG_TLS_BUILTIN and a malicious server or a server requesting client certificates; MMU-equipped targets crash, while no-MMU behavior depends on the memory map.

CVSS severity7.5
High
EPSS probability0.23%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Get started

Summary

What happened

Out-of-bounds reads in Cesanta Mongoose before 7.23 allow remote attackers to crash built-in TLS applications via crafted certificates. mg_der_to_tlv() accepts long-form lengths exceeding the certificate buffer, causing mg_der_next() to underflow its remaining-length counter and mg_tls_parse_cert_der() to walk an invalid pointer. Exposure requires MG_TLS_BUILTIN and a malicious server or a server requesting client certificates; MMU-equipped targets crash, while no-MMU behavior depends on the memory map.

The record

CVE
CVE-2026-73260
Published
Oct 14, 2026
Updated
Oct 14, 2026
Vendor
Cesanta
Product
Mongoose
Classifications
CWE-125, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 7.23

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Cesanta · Mongooseversion=< 7.23

Published CVSS scores

7.5CesantaCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Get started to see how Hinoki identifies affected software and validates exploitability in your environment.

Get started