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Medium ALAS2-2026-3844 12 CVEs

Moderate: amazon-cloudwatch-agent security update (Amazon Linux 2)

Published Aug 3, 2026 · Updated Aug 4, 2026

Ecosystem: Amazon Linux

Summary

Package updates are available for Amazon Linux 2 that fix the following vulnerabilities: CVE-2026-46598: For certain crafted inputs, a 'ed25519.PrivateKey' was created by casting malformed wire bytes, leading to a panic when used. CVE-2026-46597: An incorrectly placed cast from bytes to int allowed for server-side panic in the AES-GCM packet decoder for well-crafted inputs. CVE-2026-42507: When returning errors, functions in the net/textproto package would include its input as part of the error. This might allow an attacker to inject misleading content to errors that are printed or logged. CVE-2026-42505: 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-2026-42504: Decoding a maliciously-crafted MIME header containing many invalid encoded-words can consume excessive CPU. CVE-2026-39835: SSH servers which use CertChecker as a public key callback without setting IsUserAuthority or IsHostAuthority could be caused to panic by a client presenting a certificate. CertChecker now returns an error instead of panicking when these callbacks are nil. CVE-2026-39834: When writing data larger than 4GB in a single Write call on an SSH channel, an integer overflow in the internal payload size calculation caused the write loop to spin indefinitely, sending empty packets without making progress. The size comparison now uses int64 to prevent truncation. CVE-2026-39832: When adding a key to a remote agent constraint extensions such as restrict-destination-v00@openssh.com were not serialized in the request. Destination restrictions were silently stripped when forwarding keys, allowing unrestricted use of the key on the remote host. The client now serializes all constraint extensions. Additionally, the in-memory keyring returned by NewKeyring() now rejects keys with unsupported constraint extensions instead of silently ignoring them. CVE-2026-39828: When an SSH server authentication callback returned PartialSuccessError with non-nil Permissions, those permissions were silently discarded, potentially dropping certificate restrictions such as force-command after a second factor succeeded. Returning non-nil Permissions with PartialSuccessError now results in a connection error. CVE-2026-39827: An authenticated SSH client that repeatedly opened channels which were rejected by the server caused unbounded memory growth, eventually crashing the server process and affecting all connected users. Rejected channels are now properly removed from the connection's internal state and released for garbage collection. CVE-2026-39822: On Unix systems, opening a file in an os.Root improperly follows symlinks to locations outside of the Root when the final path component of the a path is a symbolic link and the path ends in /. For example, 'root.Open("symlink/")' will open "symlink" even when "symlink" is a symbolic link pointing outside of the root. CVE-2026-27145: (*x509.Certificate).VerifyHostname previously called matchHostnames in a loop over all DNS Subject Alternative Name (SAN) entries. This caused strings.Split(host, ".") to execute repeatedly on the same input hostname. With a large DNS SAN list, verification costs scaled quadratically based on the number of SAN entries multiplied by the hostname's label count. Because x509.Verify validates hostnames before building the certificate chain, this overhead occurred even for untrusted certificates.

Fixed packages 1

ReleasePackageFixed in
Amazon Linux · 2 amazon-cloudwatch-agent 0:1.300069.1-1.amzn2

Vulnerabilities 12

References

  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-27145.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-39822.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-39827.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-39828.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-39832.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-39834.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-39835.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-42504.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-42505.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-42507.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-46597.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-46598.html