CyberSecBulletin
CVE-2023-41378NVD status: Modified

Typha: Improper Handling of Exceptional Conditions

Published Updated By the CyberSecBulletin desk

CVE-2023-41378 is a high-severity improper handling of exceptional conditions vulnerability in Typha from Calico, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Typha versions: v3.26.0 through v3.26.2; v3.25.1 and earlier. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.89% chance of exploitation within 30 days, higher than 60% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Calico Cloud to 18.0.0 or a later version.
  2. Update Calico Enterprise to 3.15.4 or 3.16.4 or 3.17.2, whichever matches your release line, or a later version.
  3. Update Calico OS to 3.25.2 or 3.26.3, whichever matches your release line, or a later version.
  4. Read the advisory on tigera.io for workarounds and exact fixed builds.
  5. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
CalicoTyphav3.26.0 through v3.26.2; v3.25.1 and earlierNot stated
TigeraTyphav3.17.0 through v3.17.1; v3.16.0 through v3.16.3; v3.15.3 and earlierNot stated
Tigeracalicov3.17.0 through v3.17.1; v3.16.0 through v3.16.3; v3.15.3 and earlierNot stated
TigeraCalico Cloudbefore 18.0.018.0.0
TigeraCalico Enterprisebefore 3.15.4; 3.16.0 up to, but not including, 3.16.4; 3.17.0 up to, but not including, 3.17.23.15.4, 3.16.4, 3.17.2
TigeraCalico OSbefore 3.25.2; 3.26.0 up to, but not including, 3.26.33.25.2, 3.26.3

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.17.5HighCNA (tigera.io)
CVSS 3.17.5HighNVD

Official description

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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Handling of Exceptional Conditions

The product does not handle or incorrectly handles an exceptional condition.

More Improper Handling of Exceptional Conditions vulnerabilities (CWE-755)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Improper Handling of Exceptional Conditions vulnerabilities

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