Low severity · published Feb 23, 2026
CVE-2026-2966
Cesanta Mongoose DNS Transaction ID dns.c mg_sendnsreq random values
3.7
CVSS
0.4%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
None
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 38% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MO
Mongoose · Cesanta
7.0; 7.1; 7.2; 7.3; 7.4; 7.5; +15 more · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-2966
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-2966
Exploit
https://github.com/dwBruijn/CVEs/blob/main/Mongoose/mg_sendnsreq.md
Exploit
https://github.com/dwBruijn/CVEs/blob/main/Mongoose/mg_sendnsreq.md#poc
Permissions Required
https://vuldb.com/?ctiid.347333
Third Party Advisory
https://vuldb.com/?id.347333
Third Party Advisory
https://vuldb.com/?submit.755304
More from Mongoose
9.8
CVE-2026-5244
Cesanta Mongoose TLS 1.3 mongoose.c mg_tls_recv_cert heap-based overflow
9.8
CVE-2024-42383
Use of Out-of-range Pointer Offset vulnerability in Cesanta Mongoose Web Server v7.14 allows to write a NULL byte value beyond the memory space dedicated for the hostname field
9.8
CVE-2020-25756
A buffer overflow vulnerability exists in the mg_get_http_header function in Cesanta Mongoose 6.18 due to a lack of bounds checking
9.8
CVE-2019-19307
An integer overflow in parse_mqtt in mongoose.c in Cesanta Mongoose 6.16 allows an attacker to achieve remote DoS (infinite loop), or possibly cause an out-of-bounds write, by…
9.8
CVE-2019-12951
An issue was discovered in Mongoose before 6.15