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CVE Record

CVE-2021-24119: In Trusted Firmware Mbed TLS 2.24.0, a side-channel vulnerability in base64 PEM file decoding allows system...

In Trusted Firmware Mbed TLS 2.24.0, a side-channel vulnerability in base64 PEM file decoding allows system-level (administrator) attackers to obtain information about secret RSA keys via a controlled-channel and side-channel attack on software running in isolated environments that can be single stepped, especially Intel SGX.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-24119 is a side-channel issue in Trusted Firmware Mbed TLS 2.24.0. Under narrow conditions, an attacker who already has system-level control may infer information about secret RSA keys while PEM files are decoded, especially in isolated environments such as Intel SGX.

Executive priority

Treat this as targeted cryptographic key exposure risk, not broad remote compromise. Prioritize regulated or high-value systems using enclaves or isolated execution for private-key handling, then fold remaining remediation into normal crypto-library patch cycles.

Technical view

The vulnerability is in Mbed TLS base64 PEM file decoding. Sources describe a controlled-channel and side-channel attack against software in isolated environments that can be single-stepped. The record provides no CVSS, CWE, or complete affected-version range beyond Mbed TLS 2.24.0.

Likely exposure

Exposure is most likely where Mbed TLS 2.24.0 or vulnerable distribution packages parse PEM-encoded RSA private keys inside enclaves, TEEs, or similar isolated runtimes. General internet-facing exposure is not supported by the sources.

Exploitation context

The source bundle does not show CISA KEV listing or active exploitation. The described attacker already has administrator or system-level capability and needs side-channel observation or single-stepping access to isolated execution.

Researcher notes

Evidence is limited: no CVSS, CWE, or full affected-version matrix is provided in the bundle. Analysis should stay tied to Mbed TLS 2.24.0, PEM/base64 RSA key decoding, privileged attacker prerequisites, and SGX-like isolated execution.

Mitigation direction

  • Check Mbed TLS vendor releases for the fixed version and upgrade guidance.
  • Apply relevant operating-system security updates for Debian or Fedora packages.
  • Prioritize systems handling RSA private keys in SGX or similar isolated environments.
  • Review whether PEM private-key decoding occurs in privileged or enclave code paths.

Validation and detection

  • Inventory applications and packages using Mbed TLS, especially version 2.24.0.
  • Identify workloads that decode PEM RSA private keys in isolated environments.
  • Confirm Debian or Fedora mbedtls security updates are installed where applicable.
  • Check vendor advisories for exact fixed package versions before closing remediation.
Prepared
Confidence
medium
Sources
9

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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description · low confidence lookup

Credential and access behavior lookup

The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

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cve · low confidence lookup

CVE-2021-24119 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
8Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.