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TI-2026-02558 Aliases CVE-2026-2966GHSA-m5mm-h952-fxjj

Cesanta Mongoose DNS Transaction ID dns.c mg_sendnsreq random values

Priority MEDIUM 61CWE-310Published · Updated

Key facts

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

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

A weakness has been identified in Cesanta Mongoose up to 7.20. The impacted element is the function mg_sendnsreq of the file /src/dns.c of the component DNS Transaction ID Handler. Executing a manipulation of the argument random can lead to insufficiently random values. The attack can be launched remotely. The attack requires a high level of complexity. The exploitability is regarded as difficult. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00441 38th percentileScored 2026-11-07
Public exploit Yes 2 exploit referencesTagged by NVD and the CNA
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
CesantaMongoose7.0; 7.1; 7.2; 7.3; 7.4; 7.5; 7.6; 7.7; 7.8; 7.9; 7.10; 7.11; 7.12; 7.13; 7.14; 7.15; 7.16; 7.17; 7.18; 7.19; 7.20—No fix listedCNA
  • Mongoose VendorCesanta Affected 7.0; 7.1; 7.2; 7.3; 7.4; 7.5; 7.6; 7.7; 7.8; 7.9; 7.10; 7.11; 7.12; 7.13; 7.14; 7.15; 7.16; 7.17; 7.18; 7.19; 7.20 Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:cesanta:mongoose:*:*:*:*:*:*:*:*up to 7.20VulnerableCesanta
  • cpe:2.3:a:cesanta:mongoose:*:*:*:*:*:*:*:* Versions up to 7.20 Vulnerable ·Cesanta

Remediation

No fixed version listed by the sources yet.

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-2966
  2. 2026-10-03 Alias added: GHSA-m5mm-h952-fxjj

References

Exploit 2

  • 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