CVE-2026-5244
CVE-2026-5244 — Cesanta Mongoose TLS 1.3 mongoose.c mg_tls_recv_cert heap-based overflow
A vulnerability has been found in Cesanta Mongoose up to 7.20. This affects the function mg_tls_recv_cert of the file mongoose.c of the component TLS 1.3 Handler. Such manipulation of the argument pubkey leads to heap-based buffer overflow. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. Upgrading to version 7.21 mitigates this issue. The name of the patch is 0d882f1b43ff2308b7486a56a9d60cd6dba8a3f1. It is advisable to upgrade the affected component. The vendor was contacted early, responded in a very professional manner and quickly released a fixed version of the affected product.
Published Updated Sources: cvelistV5, VulDB
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.
Exploitation
Unreported
no source claims exploitation
EPSS
1%
chance of exploitation in 30 days
CVSS base
7.3
HIGH
CISA SSVC assessment
Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.
Exploitation
None
none · proof-of-concept · active
Automatable
Yes
can an attacker script all four kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component
Affected scope
The catalog records vendors and products as separate lists, not pairs, so which product belongs to which vendor is not something this page can say.
Vendors (1)
Products (1)
Every base score collected
Sources score independently and disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Source |
|---|---|---|---|---|---|
| 7.3 | CVSS 3.1 | HIGH | — | — | cvelistV5 |
Weakness & attack patterns
- CWE-122
- CWE-119
References
6 on the record
- vuldb.com/vuln/354825
vdb-entry, technical-description
- vuldb.com/vuln/354825/cti
signature, permissions-required
- vuldb.com/submit/770063
third-party-advisory
- github.com/cesanta/mongoose/commit/0d882f1b43ff2308b7486a56a9d60cd6dba8a3f1
patch
- github.com/cesanta/mongoose/releases/tag/7.21
patch
- github.com/cesanta/mongoose/
product
Elsewhere on this site
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.