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TI-2021-08271 Aliases CVE-2021-26530GHSA-j5hw-64m5-6442

The mg_tls_init function in Cesanta Mongoose HTTPS server 7.0 (compiled with OpenSSL…

Priority MEDIUM 42CWE-787Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · High · High
Fix status
No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA.

Summary

The mg_tls_init function in Cesanta Mongoose HTTPS server 7.0 (compiled with OpenSSL support) is vulnerable to remote OOB write attack via connection request after exhausting memory pool.

Why it matters now

EPSS 0.01509 74th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix No fix listed No fixed version in the sources yet

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
——all versions—No fix listedCNA
  • — Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:cesanta:mongoose:7.0:*:*:*:*:*:*:*7.0VulnerableCesanta
  • cpe:2.3:a:cesanta:mongoose:7.0:*:*:*:*:*:*:* Versions 7.0 Vulnerable ·Cesanta

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-26530
  2. 2026-10-03 Alias added: GHSA-j5hw-64m5-6442

References

Exploit 1

  • TI-2026-51393 Mongoose: Content-Length + Transfer-Encoding coexistence enables request smuggling CVSS 3.1CRITICAL 9.1
  • TI-2026-51389 Mongoose: TLS Hostname Verification Bypass via Overly Permissive Wildcard Matching CVSS 4.0CRITICAL 9.1
  • TI-2023-02723 Cesanta Mongoose MQTT Message Parsing Heap Overflow CVSS 3.1HIGH 8.8
  • TI-2020-15865 Buffer overflow in mg_resolve_from_hosts_file in Mongoose 6.18, when reading from a crafted hosts file. CVSS 3.1HIGH 8.8
  • TI-2023-17032 The HTTP server in Mongoose before 7.10 accepts requests containing negative… CVSS 3.1HIGH 7.5
  • TI-2026-06113 Cesanta Mongoose TCP Option net_builtin.c handle_opt infinite loop CVSS 4.0MEDIUM 6.9
See all 54 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences