Amazon Linux 2 : containerd, --advisory ALAS2NITRO-ENCLAVES-2026-109 (ALASNITRO-ENCLAVES-2026-109)

critical Nessus Plugin ID 319772

Synopsis

The remote Amazon Linux 2 host is missing a security update.

Description

The version of containerd installed on the remote host is prior to 2.1.7-1. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2NITRO-ENCLAVES-2026-109 advisory.

The RSA and DSA public key parsers did not enforce size limits on key parameters. A crafted public key with an excessively large modulus or DSA parameter could cause several minutes of CPU consumption during signature verification. This could be triggered by unauthenticated clients during public key authentication. RSA moduli are now limited to 8192 bits, and DSA parameters are validated per FIPS 186-2.
(CVE-2026-39829)

A malicious SSH peer could send unsolicited global request responses to fill an internal buffer, blocking the connection's read loop. The blocked goroutine could not be released by calling Close(), resulting in a resource leak per connection. Unsolicited global responses are now discarded. (CVE-2026-39830)

The Verify() method for FIDO/U2F security key types ([email protected], sk-ssh- [email protected]) did not check the User Presence flag. Signatures generated without physical touch were accepted, allowing unattended use of a hardware security key. To restore the previous behavior, return a no-touch-required extension in Permissions.Extensions from PublicKeyCallback. (CVE-2026-39831)

The in-memory keyring returned by NewKeyring() silently accepted keys with the ConfirmBeforeUse constraint but never enforced it. The key would sign without any confirmation prompt, with no indication to the caller that the constraint was not in effect. NewKeyring() now returns an error when unsupported constraints are requested. (CVE-2026-39833)

Previously, a revoked 'SignatureKey' belonging to a CA was not correctly checked for revocation. Now, both the 'key' and 'key.SignatureKey' are checked for @revoked. (CVE-2026-42508)

Previously, CVE-2024-45337 fixed an authorization bypass for misused ssh server configurations; if any other type of callback is passed other than public key, then the source-address validation would be skipped. (CVE-2026-46595)

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 'yum update containerd' or or 'yum update --advisory ALAS2NITRO-ENCLAVES-2026-109' to update your system.

Plugin Details

Severity: Critical

ID: 319772

File Name: al2_ALASNITRO-ENCLAVES-2026-109.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 6/8/2026

Updated: 6/8/2026

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: High

Score: 8.1

CVSS v2

Risk Factor: High

Base Score: 9.4

Temporal Score: 7

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

CVSS Score Source: CVE-2026-42508

CVSS v3

Risk Factor: Critical

Base Score: 10

Temporal Score: 8.7

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

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

CVSS Score Source: CVE-2026-46595

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:containerd-stress, cpe:/o:amazon:linux:2, p-cpe:/a:amazon:linux:containerd, p-cpe:/a:amazon:linux:containerd-debuginfo

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

Exploit Ease: No known exploits are available

Patch Publication Date: 6/8/2026

Vulnerability Publication Date: 5/12/2026

Reference Information

CVE: CVE-2026-39829, CVE-2026-39830, CVE-2026-39831, CVE-2026-39833, CVE-2026-42508, CVE-2026-46595

IAVB: 2026-B-0120

Detections

Analytics