Gnutls
CVE-2020-13777
HIGH
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A04:2025 - Cryptographic Failures
ASVS 5.0
V11 - Cryptography Approved algorithm selection
|
| Impact | CVSS score of 7.4 (HIGH). Attack characteristics: network attack vector, high complexity, no privileges required, no user interaction not required. |
| Exploit ScenarioDerived | This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the high-severity affected system. |
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Alert meAnalysisAI
GnuTLS 3.6.x before 3.6.14 uses incorrect cryptography for encrypting a session ticket (a loss of confidentiality in TLS 1.2, and an authentication bypass in TLS 1.3). Rated high severity (CVSS 7.4), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.
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Technical ContextAI · show details
This vulnerability is classified under CWE-327. GnuTLS 3.6.x before 3.6.14 uses incorrect cryptography for encrypting a session ticket (a loss of confidentiality in TLS 1.2, and an authentication bypass in TLS 1.3). The earliest affected version is 3.6.4 (2018-09-24) because of an error in a 2018-09-18 commit. Until the first key rotation, the TLS server always uses wrong data in place of an encryption key derived from an application. Affected products include: Gnu Gnutls, Fedoraproject Fedora, Canonical Ubuntu Linux, Debian Debian Linux. Version information: before 3.6.14.
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Severity by source
AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
GnuTLS 3.6.x before 3.6.14 uses incorrect cryptography for encrypting a session ticket (a loss of confidentiality in TLS 1.2, and an authentication bypass in TLS 1.3). The earliest affected version is 3.6.4 (2018-09-24) because of an error in a 2018-09-18 commit. Until the first key rotation, the TLS server always uses wrong data in place of an encryption key derived from an application.
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
Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.
Affected Products (CPE)NVD
A flaw was found in gnutls. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentic
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
GitHub PoC
Exploit-DB