RSA PKCS#1 v1.5 padding oracle via legacy envelope key format downgrade in Amazon S3 Encryption Client for .NET
Exact source revision recorded 23 Oct 2026 15:48:27 UTC. It does not establish the source's current position. Latest evidence.
cve-program · CVE-2026-110310
PublishedA remote user who can read encrypted objects in the S3 bucket can force a padding downgrade by altering the padding scheme recorded in an object's metadata to legacy PKCS#1 v1.5. Since this padding scheme is susceptible to the well-known Bleichenbacher attack, the user can use a PKCS#1 v1.5 padding oracle to recover the RSA-wrapped envelope key and decrypt the object. To remediate this issue, we recommend that users upgrade to version 3.2.2 or 4.0.3. The 1.x and 2.x lines will not be patched, users of those lines need to migrate to 3.2.2 or 4.0.3.
- Source published
- 14 Oct 2026 19:37:48 UTC
- Source modified
- 14 Oct 2026 19:46:28 UTC
- Observed here
- 23 Oct 2026 15:48:27 UTC
- Source terms
- CVE Program Terms of Use
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CVSS 3.1 · 5.3 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
CVSS 4.0 · 6.0 CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N