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Vulnerabilities

Vulnerability · CVE-2026-6550

Cryptographic algorithm downgrade in the caching layer of Amazon AWS Encryption SDK for Python before version 3.3.1 and before version 4.0.5 might allow an authenticat…

Published Apr 20, 2026 · catalog updated Jun 17, 2026 · the affected product

Last checked Oct 25, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-6550. EPSS is 0.10%. Act only if a listed version of the affected product is installed.

Gaps on this record

  • No plain product name is stored. The page cannot tell you which product to check.
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium5.7
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.10%
Remediation
Advisory link
Affected products
See sources for product scope

Cryptographic algorithm downgrade in the caching layer of Amazon AWS Encryption SDK for Python before version 3.3.1 and before version 4.0.5 might allow an authenticated local threat actor to bypass key commitment policy enforcement via a shared key cache, resulting in ciphertext that can be decrypted to multiple different plaintexts. To remediate this issue, users should upgrade to version 3.3.1, 4.0.5 or above.

No affected version ranges are stored yet. Use the vendor advisory before you decide this record does not apply.

How to fix CVE-2026-6550

  • No stored fix

    No vendor fix text is stored. Use the linked advisory before you change production.

  • Version check

    No version range is stored, so an installed version cannot be checked on this page.

  • Advisory

    Open the cve_org record and follow its fix.

  • Official advisories

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-6550. EPSS is 0.10%. Act only if a listed version of the affected product is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-757. EPSS 0.10%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 20, 2026 · NIST NVD

    Detected

    Cryptographic algorithm downgrade in the caching layer of Amazon AWS Encryption SDK for Python before version 3.3.1 and before version 4.0.5 might allow an authenticated local threat actor to bypass key commitment policy enforcement via a shared key cache, resulting in ciphertext that can be decrypted to multiple different plaintexts. To remediate this issue, users should upgrade to version 3.3.1,

  2. Jun 17, 2026 · NIST NVD

    Updated

    Cryptographic algorithm downgrade in the caching layer of Amazon AWS Encryption SDK for Python before version 3.3.1 and before version 4.0.5 might allow an authenticated local threat actor to bypass key commitment policy enforcement via a shared key cache, resulting in ciphertext that can be decrypted to multiple different plaintexts. To remediate this issue, users should upgrade to version 3.3.1,

Sources

  • CVE.orgVulnerability recordCVE-2026-6550

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-6550

    30-day exploitation probability 0.10%

    first.org
  • NIST NVDVulnerability recordCVE-2026-6550

    Cryptographic algorithm downgrade in the caching layer of Amazon AWS Encryption SDK for Python before version 3.3.1 and before version 4.0.5 might allow an authenticated local threat actor to bypass key commitment policy enforcement via a shared key cache, resulting in ciphertex

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 25, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSOct 25, 2026
  • CVE.orgOct 16, 2026
  • NIST NVDOct 15, 2026