Detections
Analytics
SCA: security update for org.http4s:blaze-core_2.11, org.http4s:blaze-core_2.12, org.http4s:blaze-core_2.13 (GHSA-xmw9-q7x9-j5qc)
high Tenable Cloud Security Plugin ID 420587
Description
There are packages installed that are affected by a vulnerability referenced in the following CVE:- blaze is a Scala library for building asynchronous pipelines, with a focus on network IO. All servers
running blaze-core before version 0.14.15 are affected by a vulnerability in which unbounded connection
acceptance leads to file handle exhaustion. Blaze, accepts connections unconditionally on a dedicated
thread pool. This has the net effect of amplifying degradation in services that are unable to handle their
current request load, since incoming connections are still accepted and added to an unbounded queue. Each
connection allocates a socket handle, which drains a scarce OS resource. This can also confound higher
level circuit breakers which work based on detecting failed connections. The vast majority of affected
users are using it as part of http4s-blaze-server <= 0.21.16. http4s provides a mechanism for limiting
open connections, but is enforced inside the Blaze accept loop, after the connection is accepted and the
socket opened. Thus, the limit only prevents the number of connections which can be simultaneously
processed, not the number of connections which can be held open. The issue is fixed in version 0.14.15 for
"NIO1SocketServerGroup". A "maxConnections" parameter is added, with a default value of 512. Concurrent
connections beyond this limit are rejected. To run unbounded, which is not recommended, set a negative
number. The "NIO2SocketServerGroup" has no such setting and is now deprecated. There are several possible
workarounds described in the refrenced GitHub Advisory GHSA-xmw9-q7x9-j5qc. (CVE-2021-21293)
See Also
Plugin Details
Severity: High
ID: 420587
Version: Revision 1.4
Type: Local
Family: SCA Checks
Published: 1/23/2025
Updated: 7/2/2026
Supported Sensors: Tenable Cloud Security, Tenable Self-Hosted Container Security
Risk Information
VPR
Risk Factor: Low
Score: 3
Percentile: 23.18
Vendor
Vendor Severity: High
CVSS v2
Risk Factor: Medium
Base Score: 5
Temporal Score: 3.7
Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P
CVSS Score Source: CVE-2021-21293
CVSS v3
Risk Factor: High
Base Score: 7.5
Temporal Score: 6.5
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C
Vulnerability Information
Exploit Ease: No known exploits are available
Patch Publication Date: 2/2/2021
Vulnerability Publication Date: 2/2/2021
Reference Information
CVE: CVE-2021-21293