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CVE Record

CVE-2023-3724: TLS 1.3 client issue handling malicious server when not including a KSE and PSK extension

If a TLS 1.3 client gets neither a PSK (pre shared key) extension nor a KSE (key share extension) when connecting to a malicious server, a default predictable buffer gets used for the IKM (Input Keying Material) value when generating the session master secret. Using a potentially known IKM value when generating the session master secret key compromises the key generated, allowing an eavesdropper to reconstruct it and potentially allowing access to or meddling with message contents in the session. This issue does not affect client validation of connected servers, nor expose private key information, but could result in an insecure TLS 1.3 session when not controlling both sides of the connection. wolfSSL recommends that TLS 1.3 client side users update the version of wolfSSL used.

CriticalCVSS 9.1Not KEV-listedUpdated
Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

A malicious TLS 1.3 server could cause affected wolfSSL clients to build session keys from predictable material. That can make the encrypted session readable or modifiable by an eavesdropper. The sources say server identity validation and private keys are not exposed, but client-side TLS confidentiality and integrity can fail.

Executive priority

Treat this as urgent for products or services using wolfSSL 3.14.0 as a client. It can undermine TLS confidentiality and integrity, but the provided evidence does not show active exploitation or private-key disclosure.

Technical view

In wolfSSL 3.14.0, a TLS 1.3 client receiving neither PSK nor key-share extension may use a default predictable IKM while generating the session master secret. That weakens the derived session keys and can compromise confidentiality and integrity for that session.

Likely exposure

Exposure is most relevant where products embed wolfSSL 3.14.0 as a TLS 1.3 client and connect to servers outside the organization’s control. The supplied sources list wolfSSL 3.14.0 specifically and mark other versions as unaffected by default.

Exploitation context

The CVE requires a malicious server and an eavesdropper position to benefit from the predictable session key material. The CVE is not listed as KEV, and the supplied sources do not provide evidence of active exploitation.

Researcher notes

The key boundary is client-side wolfSSL 3.14.0 behavior when a malicious TLS 1.3 server omits both PSK and key-share extension. Do not infer broader affected versions from the supplied sources. The public references identify an upstream patch and vendor security page, but no exploit-in-the-wild evidence.

Mitigation direction

  • Inventory applications and devices embedding wolfSSL 3.14.0.
  • Update affected wolfSSL client deployments per wolfSSL security guidance.
  • Apply the referenced upstream patch if vendor upgrade guidance requires source-level remediation.
  • Prioritize clients that connect to untrusted or internet-controlled TLS servers.
  • Track downstream vendor advisories for products bundling wolfSSL.

Validation and detection

  • Confirm whether deployed binaries or SBOMs include wolfSSL 3.14.0.
  • Verify TLS 1.3 client functionality after upgrading wolfSSL.
  • Check vendor advisories for the fixed release applicable to each product.
  • Review regression tests for malformed TLS 1.3 server handshake handling.
Prepared
Confidence
high
Sources
4

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

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ATT&CK lookup starting points

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cwe · low confidence lookup

CWE-20: Exact CWE lookup

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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-2023-3724 mapping review

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Vulnerability profileCVE Program record
Severity
Critical
CVSS
9.1 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

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.

1CVSS vectors
0Timeline events
0ADP providers
3Source links

CVSS vector scores

1 official score

We 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.

ScoreVersionSeverityVectorExploitImpactSource
9.1CVSS 3.1CriticalCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H2.36Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

9.1Critical
CVSS 3.1 vector shape for CVE-2023-3724Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
wolfSSLwolfSSL3.14.0unaffected
Weakness

CWE details

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

CWE-20 · source CWE mapping

Improper Input Validation

Improper Input Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.