> CVE-2021-27137 [HIGH]

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PUBLISHED
2026-07-16 18:16
MODIFIED
2026-07-16 18:16
CVSS_SCORE V3
8.1
EPSS (Prob. Exploit)
4.00%
Top 9.5%
⚠ CISA_KEV
DATA SOURCES:
NVD 🔗 2026-07-16 CISA KEV 🔗 CWE MITRE 🔗 2026-11-01 FIRST EPSS 🔗 2026-10-25

> DESCRIPTION

An issue was discovered in router/upnp/src/ssdp.c in DD-WRT before 45724. An unsafe strcpy in the UPnP handling functionality allows an unauthenticated remote attacker to send a request that would overflow an internal fixed buffer. Exploitation requires the DD-WRT user to enable UPnP (which is off by default, and only listens on internal interfaces by default). This occurs in ssdp_msearch (reachable by an M-SEARCH request).

> AFFECTED_PRODUCTS

Dd-Wrt - DD-WRT

> CVSS V3 METRICS

CVSS_VECTOR
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
EXPLOITABILITY
2.2
IMPACT
5.9

> MÉTRIQUES CVSS DÉTAILLÉES

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Métrique Valeur Interprétation
AV (Vecteur d'Attaque)
Attack Vector
Network (N)
Exploit possible à distance via réseau (HTTP, API, etc.)
AC (Complexité d'Attaque)
Attack Complexity
High (H)
Conditions spécifiques doivent être réunies pour exploiter
PR (Privilèges Requis)
Privileges Required
None (N)
Aucune authentification requise
UI (Interaction Utilisateur)
User Interaction
None (N)
Aucune interaction utilisateur nécessaire
S (Périmètre)
Scope
Unchanged (U)
Impact reste dans le périmètre du composant compromis
C (Impact Confidentialité)
Confidentiality Impact
High (H)
Divulgation totale d'informations
I (Impact Intégrité)
Integrity Impact
High (H)
Modification totale des données possible
A (Impact Disponibilité)
Availability Impact
High (H)
Interruption totale du service possible

> RÉSUMÉ DES IMPACTS

Confidentialité
High
Divulgation totale d'informations
Intégrité
High
Modification totale des données possible
Disponibilité
High
Interruption totale du service possible

> WEAKNESSES

CWE-121

> CWE DETAILED DESCRIPTIONS

CWE-121: Stack-based Buffer Overflow - The product writes past the end of a buffer that was allocated on the stack.

> HISTORIQUE DES MODIFICATIONS

Première apparition
16/07/2026 18:16
Source: NVD
📊 ENRICHISSEMENT 01/11/2026 06:59
CWE
Champ modifié: Description CWE
Ancienne valeur:
CWE-121: Stack-based Buffer Overflow - A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a para...
Nouvelle valeur:
CWE-121: Stack-based Buffer Overflow - The product writes past the end of a buffer that was allocated on the stack.
📊 ENRICHISSEMENT 01/08/2026 06:01
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-121: Stack-based Buffer Overflow - A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a para...
📊 ENRICHISSEMENT 21/07/2026 15:15
KEV
Champ modifié: Catalogue KEV
Ancienne valeur:
Non
Nouvelle valeur:
Oui
Total des modifications: 3 Dernière mise à jour: 5 days ago

> REFERENCES

https://securityaffairs.com/193290/uncategorized/iot-botnet-c0xmo-adds-competito...
https://ssd-disclosure.com/ssd-advisory-dd-wrt-upnp-buffer-overflow/
https://svn.dd-wrt.com/changeset/45724
https://www.bleepingcomputer.com/news/security/c0xmo-botnet-spreads-via-dd-wrt-r...
https://www.fortinet.com/blog/threat-research/inside-cross-platform-propagation-...
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