Gnutls
CVE-2021-20231
CRITICAL
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Memory lifecycle management
MITRE ATT&CK
2 techniques across 2 tactics: Execution, Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 9.8 (CRITICAL). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. Public proof-of-concept exploit code is available. |
| Exploit ScenarioDerived | A remote attacker could access freed memory to execute arbitrary code or crash the application by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability. |
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Alert meAnalysisAI
A flaw was found in gnutls. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
RemediationAI
A vendor patch is available. Apply the latest security update as soon as possible. Use smart pointers or garbage-collected languages. Set pointers to NULL after freeing. Enable memory sanitizers.
Affects your stack
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Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
This vulnerability is classified as Use After Free (CWE-416), which allows attackers to access freed memory to execute arbitrary code or crash the application. A flaw was found in gnutls. A use after free issue in client sending key_share extension may lead to memory corruption and other consequences. Affected products include: Gnu Gnutls, Redhat Enterprise Linux, Fedoraproject Fedora, Netapp Active Iq Unified Manager, Netapp E-Series Performance Analyzer.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
A flaw was found in gnutls. A use after free issue in client sending key_share extension may lead to memory corruption and other consequences.
Threat Intelligence Overview
NVD
CVE.org
EPSS
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.
Use-after-free vulnerabilities occur when a program continues to access memory through a pointer after that memory has been deallocated.
Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
Affected Products (CPE)NVD
Buffer overflow in the read_server_hello function in lib/gnutls_handshake.c in GnuTLS before 3.1.25, 3.2.x before 3.2.15
An issue was discovered in GnuTLS before 3.6.15. Rated high severity (CVSS 7.5), this vulnerability is remotely exploita
A vulnerability was found in GnuTLS. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no auth
Alpine Linux: gnutls fixed in 3.8.3-r0
Double free vulnerability in libgnutls in GnuTLS before 3.0.14 allows remote attackers to cause a denial of service (app
A timing side-channel in the handling of RSA ClientKeyExchange messages was discovered in GnuTLS. Rated high severity (C
It was discovered in gnutls before version 3.6.7 upstream that there is an uninitialized pointer access in gnutls versio
A vulnerability was found in gnutls versions from 3.5.8 before 3.6.7. Rated high severity (CVSS 7.5), this vulnerability
The asn1_get_length_der function in decoding.c in GNU Libtasn1 before 2.12, as used in GnuTLS before 3.0.16 and other pr
Double free vulnerability in the gnutls_x509_ext_import_proxy function in GnuTLS before 3.3.26 and 3.5.x before 3.5.8 al
gnutls_cipher.c in libgnutls in GnuTLS before 2.12.17 and 3.x before 3.0.15 does not properly handle data encrypted with
GnuTLS 3.6.x before 3.6.14 uses incorrect cryptography for encrypting a session ticket (a loss of confidentiality in TLS
GitHub PoC
Exploit-DB