CVE-2026-5244
highA 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.
7.3
cvss
high
common vulnerability scoring system v3.1. measures intrinsic severity on a 0-10 scale.
epss
0.0006
kev
no
cisa known exploited vulnerabilities catalog. confirmed active exploitation.
CVSS 3.1
Common Vulnerability Scoring System v3.1
7.3
/ 10
HIGH
exploitability
Attack Vector
Network
Attack Vector (AV:N): exploitable remotely over the network — most dangerous. no physical or adjacent access needed.
Attack Complexity
Low
Attack Complexity (AC:L): no special conditions needed. attack can be reliably reproduced.
Privileges Required
None
Privileges Required (PR:N): no authentication needed. any anonymous attacker can exploit this.
User Interaction
None
User Interaction (UI:N): no victim action needed. fully exploitable without user interaction.
impact
Scope
Unchanged
Scope (S:U): impact limited to the vulnerable component.
Confidentiality
Low
Confidentiality (C:L): limited data exposure. some restricted information can be read.
Integrity
Low
Integrity (I:L): limited data modification. some data can be altered.
Availability
Low
Availability (A:L): reduced performance or partial service interruption.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
CVSS 4.0
Common Vulnerability Scoring System v4.0
6.9
/ 10
MEDIUM
exploitability
Attack Vector
Network
Attack Vector (AV:N): exploitable remotely over the network — most dangerous. no physical or adjacent access needed.
Attack Complexity
Low
Attack Complexity (AC:L): no special conditions needed. attack can be reliably reproduced.
Attack Requirements
None
Attack Requirements (AT:N): no special deployment or execution conditions needed.
Privileges Required
None
Privileges Required (PR:N): no authentication needed. any anonymous attacker can exploit this.
User Interaction
None
User Interaction (UI:N): no victim action needed. fully exploitable without user interaction.
vulnerable system impact
Vuln Confidentiality
Low
Confidentiality (VC:L): limited data exposure. some restricted information can be read.
Vuln Integrity
Low
Integrity (VI:L): limited data modification. some data can be altered.
Vuln Availability
Low
Availability (VA:L): reduced performance or partial service interruption.
subsequent system impact
Sub Confidentiality
None
Subsequent Confidentiality: impact on data confidentiality of downstream/connected systems. Value: N (None)
Sub Integrity
None
Subsequent Integrity: impact on data integrity of downstream/connected systems. Value: N (None)
Sub Availability
None
Subsequent Availability: impact on service availability of downstream/connected systems. Value: N (None)
supplemental
exploit maturity: poc
Exploit Maturity: has a functional exploit been observed? Attacked = actively exploited. PoC = proof-of-concept exists. Unreported = no known exploit.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
activity density
rdintel assessment
composite score from 15+ signals including exploitation status, epss probability, detection coverage, and community attention. 0-100 scale.
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