Vulnpedia
← Search CVEs

CVE-2026-110310

MEDIUM 6

Published 2026-10-14 · Last modified 2026-10-14

A 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.

NO EXPLOITATION SIGNALS

No known exploitation, public exploit, or elevated probability at this time. Track for changes.

Exploitation likelihood

0.5%chance of exploitation in 30 days · 43rd percentile

○ In CISA KEV ○ Catalogued PoC

Impact if exploited

6CVSS 4.0 · MEDIUM

  • ConfidentialityHigh
  • IntegrityNone
  • AvailabilityNone

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ⚠Privileges: Requires a low-privilege account
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable
  • ⚠Requirements: Specific conditions must be present

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

No public PoC is currently catalogued.

Search for new PoCs

Search GitHub now — results may be empty or unverified.

Tracked sources are checked daily for recent CVEs, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.

Data snapshot:

Affected

Vendors Amazon

Products Amazon.Extensions.S3.Encryption

Weakness (CWE)

  • CWE-204: Observable response discrepancy
  • CWE-757: Selection of Less-Secure algorithm during negotiation ('algorithm downgrade')

CVSS vector

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

References and research data (JSON)

All CVSS metrics

  • MEDIUM 5.3 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
  • MEDIUM 6 v4.0 · CNA Primary
    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
  • MEDIUM 6 v4.0 · NVD Secondary
    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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
  • MEDIUM 5.3 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

References

Patches & mitigations

Advisories

Sources: NVD · CVE.org · EPSS