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High ALAS2-2026-3809 9 CVEs

Important: amazon-ssm-agent security update (Amazon Linux 2)

Published Jul 20, 2026 · Updated Jul 20, 2026

Ecosystem: Amazon Linux

Summary

Package updates are available for Amazon Linux 2 that fix the following vulnerabilities: 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-2026-42508: 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-2026-41506: go-git is an extensible git implementation library written in pure Go. Prior to versions 5.18.0 and 6.0.0-alpha.2, go-git may leak HTTP authentication credentials when following redirects during smart-HTTP clone and fetch operations. This issue has been patched in versions 5.18.0 and 6.0.0-alpha.2. 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-2026-39831: The Verify() method for FIDO/U2F security key types (sk-ecdsa-sha2-nistp256@openssh.com, sk-ssh-ed25519@openssh.com) 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-2026-39830: 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-2026-39829: 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-2026-39827: 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.

Fixed packages 1

ReleasePackageFixed in
Amazon Linux · 2 amazon-ssm-agent 0:3.3.4624.0-1.amzn2

Vulnerabilities 9

References

  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-39827.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-39829.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-39830.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-39831.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-2026-41506.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-42508.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-46597.html