Amazon Linux 2023 : containerd, containerd-stress (ALAS2023-2026-3273)

medium Nessus Plugin ID 371911

Synopsis

The remote Amazon Linux 2023 host is missing a security update.

Description

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-3273 advisory.

containerd is an open-source container runtime. Prior to versions 1.7.36, 2.0.13, 2.2.9, 2.3.6, and 2.4.1, a crafted OCI index graph can force very high CPU/memory usage during PullImage (before container start), causing long ContainerCreating stalls and, at larger sizes, node/runtime instability. Versions 1.7.36, 2.0.13, 2.2.9, 2.3.6, and 2.4.1 fix the issue. (CVE-2026-53493)

Previously, after a channel has been established, a malicious peer could send crafted messages that would deadlock the entire connection. Now, we handle all RFC 4254 channel messages; global requests are handled explicitly. Then, treat all other messages as a protocol error and tear the connection down instead of buffering and blocking. (CVE-2026-56855)

The `github.com/moby/sys/user` package provides Go utilities for parsing and looking up entries in Unix- style user and group database files. Versions before 0.4.1 do not sufficiently limit entries when parsing `/etc/passwd`- or `/etc/group`-style files, allowing an attacker who can supply a specially crafted file to cause excessive memory consumption and potentially terminate the affected process due to an out-of- memory condition. This issue is patched in version 0.4.1. As a workaround, avoid parsing attacker- controlled user or group database files, or validate and limit untrusted input before parsing it.
(CVE-2026-61801)

When Trailer headers are sent by a client, the HTTP server internally uses the header values to populate the Request.Trailer map passed to the server handler. Because Request.Trailer is a map, each entry incurs memory overhead. For HTTP/2 servers, a malicious client can exploit this by sending a Trailer header that declares a large number of fields causing the server to allocate a disproportionate amount of memory while bypassing Server.MaxHeaderValueCount and Server.MaxHeaderBytes limits.This exploit is not applicable for HTTP/1 servers, which do not support multiplexing a large number of requests over one TCP connection, and whose Server.MaxHeaderBytes are calculated differently.Server.MaxHeaderValueCount and Server.MaxHeaderBytes limits are now applied towards the trailer fields declared in Trailer headers.

NOTE: https://www.openwall.com/lists/oss-security/2026/10/08/9NOTE:
https://github.com/golang/go/issues/81857NOTE: Fixed by:
https://github.com/golang/go/commit/cbb0fb8b51cba866018b8a0fb4b5458f16c5c80b (go1.27.2)NOTE: Fixed by:
https://github.com/golang/go/commit/6e049521882c944afc1e519a83971ec421dc2974 (go1.26.9) (CVE-2026-78659)

Previously, a channel registered in the mux's chanList is not usable until it is established. A malicious peer was able flood the channel's incomingRequests, deadlocking the entire connection. Now, we add an atomic established state, set when a channel becomes usable. Until such a time, handlePacket drops every packet other than the open confirmation/failure, without blocking and without tearing down the connection.
(CVE-2026-78662)

The HTTP/2 server could refund connection-level flow control twice for the same data: Once when a client resets a stream (refunding data for any sent-but-unread portion of the stream), and again when a request handler reads the buffered data.A malicious client could exploit this to bypass the configured connection- level flow control limit (MaxReceiveBufferPerConnection). Total buffered data is still limited by the concurrent stream limit and stream-level flow control.The HTTP/2 server now waits to refund connection- level flow control for reset streams until after the request handler is complete.

NOTE: https://www.openwall.com/lists/oss-security/2026/10/08/9NOTE:
https://github.com/golang/go/issues/81743NOTE: Fixed by:
https://github.com/golang/go/commit/31dc9e2449e394439498142451627af52626d7c4 (go1.27.2)NOTE: Fixed by:
https://github.com/golang/go/commit/6e049521882c944afc1e519a83971ec421dc2974 (go1.26.9) (CVE-2026-78663)

OpenTelemetry-Go is the Go implementation of OpenTelemetry. From version 1.5.0 to 1.44.0, sdk/trace.NewTracerProvider emits a TracerProvider created internal Info-level diagnostic event whose MarshalLog implementations recursively include span processor, exporter, and client configuration.
Applications that call otel.SetLogger to enable OpenTelemetry internal Info logging can therefore record OTLP gRPC and HTTP collector endpoints, the OTLP HTTP Insecure flag, and complete Zipkin collector URLs. A person or system with access to those logs can learn internal collector topology and can recover credentials or tokens embedded in Zipkin URL user information or query strings. The default OpenTelemetry logger does not emit the event, and this path does not log OTLP authentication headers, TLS key material, or span payloads. This issue is fixed in version 1.45.0. (CVE-2026-81870)

containerd is an open-source container runtime. From 2.1.0 until 2.2.7 and 2.3.4, containerd's CRI CreateContainer checkpoint restore is vulnerable because CRIU restores process security state from checkpoint data instead of enforcing the destination ContainerConfig. An attacker who can create a container from a crafted checkpoint can supply restored credentials, capabilities, no_new_privs, and seccomp state. The restored process can run as root with full capabilities and no enforced seccomp filters while CRI status reports the requested configuration. Systems that do not use CRI checkpoint restore are not affected. This issue is fixed in versions 2.2.7 and 2.3.4. (CVE-2026-95837)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Run 'dnf update containerd --releasever 2023.12.20261026' or or 'dnf update --advisory ALAS2023-2026-3273 --releasever 2023.12.20261026' to update your system.

Plugin Details

Severity: Medium

ID: 371911

File Name: al2023_ALAS2023-2026-3273.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 10/25/2026

Updated: 10/25/2026

Supported Sensors: Agentless Assessment, Continuous Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Nessus Agent, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.9

Percentile: 96.41

CVSS v2

Risk Factor: High

Base Score: 9.4

Temporal Score: 7

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:C/A:C

CVSS Score Source: CVE-2026-78663

CVSS v3

Risk Factor: Critical

Base Score: 9.1

Temporal Score: 7.9

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

CVSS v4

Risk Factor: Medium

Base Score: 6.9

Threat Score: 2.7

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

CVSS Score Source: CVE-2026-53493

Vulnerability Information

CPE: cpe:/o:amazon:linux:2023, p-cpe:/a:amazon:linux:containerd-debuginfo, p-cpe:/a:amazon:linux:containerd-debugsource, p-cpe:/a:amazon:linux:containerd-stress-debuginfo, p-cpe:/a:amazon:linux:containerd-stress, p-cpe:/a:amazon:linux:containerd

Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 10/24/2026

Vulnerability Publication Date: 9/2/2026

Reference Information

CVE: CVE-2026-53493, CVE-2026-56855, CVE-2026-61801, CVE-2026-78659, CVE-2026-78662, CVE-2026-78663, CVE-2026-81870, CVE-2026-95837

IAVA: 2026-A-1024

IAVB: 2026-B-0296-S

Detections

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