Security readout for executives and security teams
Plain-English summary
CVE-2023-6240 is a Linux kernel RSA side-channel issue in Red Hat-advised systems. A remote attacker could potentially learn enough from decryption behavior to decrypt ciphertexts or forge signatures tied to an exposed private key. The attack is high-complexity, but the confidentiality impact can be significant for services relying on affected kernel cryptography.
Executive priority
Treat this as a targeted cryptographic exposure with moderate urgency. It is not listed as actively exploited in the provided sources, but it can affect confidentiality of private-key-backed services. Patch affected RHEL 8 and 9 systems during the next security maintenance window, prioritizing externally reachable services.
Technical view
Red Hat describes a Marvin-class side-channel leakage in RSA decryption in the Linux kernel, classified as CWE-203 observable discrepancy. CVSS 3.1 is 6.5: network attack vector, high attack complexity, no privileges or user interaction, high confidentiality and low integrity impact. Affected packages include kernel and kernel-rt across listed RHEL 8 and RHEL 9 streams.
Likely exposure
Likely exposure is Red Hat Enterprise Linux 8 and 9 systems running listed affected kernel or kernel-rt builds, especially hosts exposing services that perform RSA private-key operations reachable over a network. RHEL 6 and 7 entries are marked unknown in the bundle, so their exposure cannot be concluded from these sources alone.
Exploitation context
The bundle does not show CISA KEV listing or cited evidence of active exploitation. Practical exploitation is high-complexity and depends on observable RSA decryption behavior over the network. The main concern is compromise of services using the affected private key, not broad unauthenticated code execution.
Researcher notes
Focus validation on observable RSA private-key operations and the exact kernel or kernel-rt builds listed by Red Hat. The sources identify the weakness class and impact but do not provide enough evidence to generalize exposure beyond named Red Hat packages or to assert exploitation in the wild.
Mitigation direction
- Apply the relevant Red Hat security errata for affected RHEL streams.
- Prioritize internet-facing systems performing RSA private-key operations.
- Check Red Hat guidance for exact fixed package versions and reboot requirements.
- Rotate exposed private keys if compromise is suspected or monitoring shows suspicious probing.
Validation and detection
- Inventory RHEL hosts and record installed kernel and kernel-rt package versions.
- Compare installed builds against Red Hat CVE and RHSA affected-package data.
- Identify services using RSA private keys on affected hosts.
- Confirm patched kernels are booted, not only installed.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
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
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-203: Information exposure and cloud metadata lookup
Information exposure and SSRF weaknesses can make discovery, cloud metadata, and credential material review relevant. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2023-6240 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N
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.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N2.24.2Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.5MediumVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- RHSA-2024:1881CVE reference · vendor-advisory, x_refsource_REDHAT
- RHSA-2024:1882CVE reference · vendor-advisory, x_refsource_REDHAT
- RHSA-2024:2758CVE reference · vendor-advisory, x_refsource_REDHAT
- RHSA-2024:3414CVE reference · vendor-advisory, x_refsource_REDHAT
- RHSA-2024:3421CVE reference · vendor-advisory, x_refsource_REDHAT
- RHSA-2024:3618CVE reference · vendor-advisory, x_refsource_REDHAT
- RHSA-2024:3627CVE reference · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/security/cve/CVE-2023-6240CVE reference · vdb-entry, x_refsource_REDHAT
- RHBZ#2250843CVE reference · issue-tracking, x_refsource_REDHAT
- https://people.redhat.com/~hkario/marvin/CVE reference
- https://securitypitfalls.wordpress.com/2023/10/16/experiment-with-side-channel-attacks-yourself/CVE reference
- https://security.netapp.com/advisory/ntap-20240628-0002/CVE reference · x_transferred
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Observable Discrepancy
Observable Discrepancy represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.