Mongoose: Unauthenticated remote heap out-of-bounds read in built-in TLS: off-by-one length check in mg_tls_recv_record() underflows recv_len to SIZE_MAX
CVSS score
7.5
EPSS probability
—
Risk score
0.8
Published
5 h ago
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Vulnerability description
CVE AI research
DayBreach AI Explanation
Verified against sourcesSources read
1
Source agreement
Tam uyum
Evidence confidence
%55
Short explanation
CVE-2026-73252 has been identified in the Mongoose embedded web server, where an unauthenticated remote peer can trigger a heap out-of-bounds read and cause a denial of service due to a length check issue in the built-in TLS stack.
Unauthenticated remote attackers can exploit this vulnerability prior to certificate or Finished validation to trigger a remote denial of service, presenting a significant availability risk.
What should be done?
- Update to Mongoose version 7.23 or later
- Follow vendor advisories for updates
Chain of evidence and sources
Mongoose 7.23 öncesi sürümlerde yerleşik TLS yığını, 16 baytlık kimlik doğrulama etiketine sahip TLS 1.3 kayıtlarını kabul eder.
mg_tls_recv_record() fonksiyonundaki uzunluk kontrolü, recv_len değerinin SIZE_MAX değerine düşmesine neden olur.
Kimliği doğrulanmamış kötü amaçlı bir TLS eşi, sertifika doğrulamasıtan önce yığın sınır dışı okuma tetikleyerek uzaktan hizmet reddine sebep olabilir.
Show the technical text from the sources
Mongoose is an embedded web server and network library. Prior to 7.23, the built-in TLS stack selected by MG_TLS_BUILTIN in src/tls_builtin.c accepts a TLS 1.3 record whose decrypted size is exactly the 16-byte authentication tag with no plaintext or ContentType byte. In mg_tls_recv_record(), the msgsz length check permits that record and the recv_len calculation underflows to SIZE_MAX, so a later handshake step treats stale buffer contents as a trusted message with an effectively unbounded length. An unauthenticated malicious TLS peer can trigger a heap out-of-bounds read before certificate or Finished validation, causing a remote denial of service. This issue is fixed in version 7.23.
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE: CWE-191, CWE-125
Explanation produced with the local gemini-flash-lite-latest model. Numerical metrics and the KEV, patch and exploit statuses are not determined by AI.
IMPACT: Affected Products and Software
Affected Products
The following products are affected by CVE-2026-73252 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.
| ID | VENDOR | PRODUCT | ACTION |
|---|---|---|---|
| 1 | cesanta | mongoose | View |
RED HAT CSAF/VEX: Product Impact Check
SCORING: CVSS from Multiple Sources
CVSS Scores
The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.
| SCORE | VERSION | SEVERITY | VECTOR | SOURCE |
|---|---|---|---|---|
| 7.5 | CVSS V31 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | NVD |
| 7.5 | CVSS V3_1 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | CVE CNA |
Patch and Remediation Guide
Solution & Remediation Advisory
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Public exploit and active exploitation status
Verified exploit intelligence
No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.
Weakness Classification and Attack Patterns (CWE & CAPEC)
CWE - Common Weakness Enumeration
While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-73252 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-2026-73252 weaknesses.
Attack Vector and Accessibility
Official Sources and Advisories
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