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CVE

CVE-2020-1967

Server or client applications that call the SSL_check_chain() function during or after a TLS 1.3 handshake may crash due

Server or client applications that call the SSL_check_chain() function during or after a TLS 1.3 handshake may crash due to a NULL pointer dereference as a result of incorrect handling of the "signature_algorithms_cert" TLS extension. The crash occurs if an invalid or unrecognised signature algorithm is received from the peer. This could be exploited by a malicious peer in a Denial of Service attack.

OpenSSL version 1.1.1d, 1.1.1e, and 1.1.1f are affected by this issue. This issue did not affect OpenSSL versions prior to 1.1.1d. Fixed in OpenSSL 1.1.1g (Affected 1.1.1d-1.1.1f).

HIGH · CVSS 7.5 EPSS 0.60769
Act now
  • EPSS ≥ 0.50 - high probability of exploitation in the next 30 days
  • EPSS percentile: top 2% of all CVEs by exploitation likelihood
  • Public exploit or PoC is available
  • CVSS base score ≥ 7.0
Sigma rules2 YARA rules0

Weakness Classification

Affected Packages

1
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
crates.io openssl-src HIGH fixed in 111.9.0

Sigma Hunt Rules

2
Exact rules name this CVE ID. Product rules name an affected product in their title. Related rules cover techniques used by actors who exploited this CVE. Showing the most relevant matches; the complete related set is on the full drill-down.
producthighOpenCanary - MySQL Login Attempt
producthighUncommon File Creation By Mysql Daemon Process

Scoring & Timeline

7.5
HIGH · CVSS v3.1 · openssl-security@openssl.org
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD21 Apr 2020 · 02:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Vendor Advisories

9
suse-csafopenSUSE-SU-2024:11127-1
suse-csafopenSUSE-SU-2024:11359-1
suse-csafopenSUSE-SU-2024:11360-1
siemens-csafSSA-108696
suse-csafSUSE-SU-2020:2041-1
🔗

References & Sources

30
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
http://seclists.org/fulldisclosure/2020/May/5Mailing ListThird Party Advisory
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