CVE-2023-41378 | Calico Typha hangs during unclean TLS handshake

In certain conditions for Calico Typha (v3.26.2, v3.25.1 and below), and Calico Enterprise Typha (v3.17.1, v3.16.3, v3.15.3 and below), a client TLS handshake can block the Calico Typha server indefinitely, resulting in denial of service. The TLS Handshake() call is performed inside the main server handle for loop without any timeout allowing an unclean TLS handshake to block the main loop indefinitely while other connections will be idle waiting for that handshake to finish.

Published: 2023-11-06 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-41378 is rated Moderate Risk (47.7/100): CVSS High severity, with low exploitation likelihood (EPSS 0.72%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2023-41378

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.22% 0.72% +0.50%
2 2025-11-21 0.37% 0.22% -0.15%
3 2025-11-18 — 0.37% —

Full EPSS history (7 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-41378

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2023-41378

GitHub Security Advisory for CVE-2023-41378

GHSA-5r5h-q934-cccp · Severity: high · Ecosystem: go — Calico Typha denial of service vulnerability

Affected software / configurations for CVE-2023-41378

Vendor Product Version Raw CPE
tigera calico_cloud < 18.0.0 cpe:2.3:a:tigera:calico_cloud:*:*:*:*:*:*:*:*
tigera calico_enterprise < 3.15.4 cpe:2.3:a:tigera:calico_enterprise:*:*:*:*:*:*:*:*
tigera calico_enterprise >= 3.16.0, < 3.16.4 cpe:2.3:a:tigera:calico_enterprise:*:*:*:*:*:*:*:*
tigera calico_enterprise >= 3.17.0, < 3.17.2 cpe:2.3:a:tigera:calico_enterprise:*:*:*:*:*:*:*:*
tigera calico_os < 3.25.2 cpe:2.3:o:tigera:calico_os:*:*:*:*:*:*:*:*
tigera calico_os >= 3.26.0, < 3.26.3 cpe:2.3:o:tigera:calico_os:*:*:*:*:*:*:*:*

References for CVE-2023-41378

cvelogic Threat Intelligence