CVE-2021-24117Network attack vector

RSA key disclosure via cache-traceable Base64 lookup

Published Jul 14, 2021 · Updated Aug 3, 2024

Side-channel exposure in Apache Teaclave Rust SGX SDK 1.1.3 allows remote authenticated users to recover secret RSA key information. The rust-base64 decode_chunk path indexes a 256-byte decode table with each Base64 character, exposing input-dependent cache-line accesses during PEM key decoding. Exploitation requires administrator control of a single-steppable isolated environment and cache observation; the reported consequence is RSA key disclosure only.

CVSS severity4.9
Medium
EPSS probability2.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Side-channel exposure in Apache Teaclave Rust SGX SDK 1.1.3 allows remote authenticated users to recover secret RSA key information. The rust-base64 decode_chunk path indexes a 256-byte decode table with each Base64 character, exposing input-dependent cache-line accesses during PEM key decoding. Exploitation requires administrator control of a single-steppable isolated environment and cache observation; the reported consequence is RSA key disclosure only.

The record

CVE
CVE-2021-24117
Published
Jul 14, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-203, T1552.004
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Jul 14, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.0NIST NVDAV:N/AC:L/Au:S/C:P/I:N/A:N
4.9NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-203Observable Discrepancy
T1552.004Unsecured Credentials: Private Keys

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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