A server-side request forgery issue due to improper validation of equivalent address representations in the port forwarding to remote hosts functionality in Amazon AWS Systems Manager Agent (SSM Agent) before 3.3.4851.0 on all platforms might allow an authenticated remote user to bypass the remote destination denylist and reach link-local endpoints, potentially obtaining the temporary IAM role credentials of a managed instance and acting with that role's permissions from outside the instance, via a crafted destination host value that uses an alternate representation of a denied link-local address. To remediate this issue, users should upgrade to version 3.3.4851.0 or later.

The version of amazon-ssm-agent installed on the remote host is prior to 3.3.5226.0-1. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2026-3963 advisory.

    Handshakes which used Encrypted Client Hello could be de-anonymized by a passive network observer due to a     disclosure of pre-shared key identities in the unencrypted client hello. (CVE-2026-42505)

    go-git is an extensible git implementation library written in pure Go. Prior to 5.19.2 and 6.0.0-alpha.5,     worktree operations (including checkout, status, and add) resolve symbolic links inside the working tree     without confining resolution to the worktree boundary, so a maliciously crafted repository containing a     symlink can cause go-git to read from or write to files outside the intended working directory when the     repository is cloned and its worktree operations are used. Versions 5.19.2 and 6.0.0-alpha.5.
    (CVE-2026-71556)

    go-git is an extensible git implementation library written in pure Go. Prior to 5.19.2 and 6.0.0-alpha.5,     reference names are not sanitized before being used to construct on-disk paths under the reference storage     directory, so a maliciously crafted reference name (for example containing directory-traversal sequences)     can cause go-git to write files outside the intended reference storage directory. Versions 5.19.2 and     6.0.0-alpha.5 fix the issue. (CVE-2026-71557)

    A server-side request forgery issue due to improper validation of equivalent address representations in     the port forwarding to remote hosts functionality in Amazon AWS Systems Manager Agent (SSM Agent) before     3.3.4851.0 on all platforms might allow an authenticated remote user to bypass the remote destination     denylist and reach link-local endpoints, potentially obtaining the temporary IAM role credentials of a     managed instance and acting with that role's permissions from outside the instance, via a crafted     destination host value that uses an alternate representation of a denied link-local address.



    To remediate this issue, users should upgrade to version 3.3.4851.0 or later. (CVE-2026-89049)

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.

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-3149 advisory.

    Handshakes which used Encrypted Client Hello could be de-anonymized by a passive network observer due to a     disclosure of pre-shared key identities in the unencrypted client hello. (CVE-2026-42505)

    go-git is an extensible git implementation library written in pure Go. Prior to 5.19.2 and 6.0.0-alpha.5,     worktree operations (including checkout, status, and add) resolve symbolic links inside the working tree     without confining resolution to the worktree boundary, so a maliciously crafted repository containing a     symlink can cause go-git to read from or write to files outside the intended working directory when the     repository is cloned and its worktree operations are used. Versions 5.19.2 and 6.0.0-alpha.5.
    (CVE-2026-71556)

    go-git is an extensible git implementation library written in pure Go. Prior to 5.19.2 and 6.0.0-alpha.5,     reference names are not sanitized before being used to construct on-disk paths under the reference storage     directory, so a maliciously crafted reference name (for example containing directory-traversal sequences)     can cause go-git to write files outside the intended reference storage directory. Versions 5.19.2 and     6.0.0-alpha.5 fix the issue. (CVE-2026-71557)

    A server-side request forgery issue due to improper validation of equivalent address representations in     the port forwarding to remote hosts functionality in Amazon AWS Systems Manager Agent (SSM Agent) before     3.3.4851.0 on all platforms might allow an authenticated remote user to bypass the remote destination     denylist and reach link-local endpoints, potentially obtaining the temporary IAM role credentials of a     managed instance and acting with that role's permissions from outside the instance, via a crafted     destination host value that uses an alternate representation of a denied link-local address.



    To remediate this issue, users should upgrade to version 3.3.4851.0 or later. (CVE-2026-89049)

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.

ID	Name	Product	Family	Type	Severity
358434	Amazon Linux 2 : amazon-ssm-agent (ALAS-2026-3963)	Nessus	Amazon Linux Local Security Checks	Local	high
353440	Amazon Linux 2023 : amazon-ssm-agent (ALAS2023-2026-3149)	Nessus	Amazon Linux Local Security Checks	Local	high

Detections

Analytics

CVE-2026-89049

high

Tenable Plugins

high

high