LiveActive security incident?Get immediate response
CVE Record

CVE-2026-3338: PKCS7_verify Signature Validation Bypass in AWS-LC

Improper signature validation in PKCS7_verify() in AWS-LC allows an unauthenticated user to bypass signature verification when processing PKCS7 objects with Authenticated Attributes. Customers of AWS services do not need to take action. Applications using AWS-LC should upgrade to AWS-LC version 1.69.0.

HighCVSS 8.7Not KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

Affected applications may accept tampered PKCS7 signed data as authentic because AWS-LC can incorrectly validate signatures containing Authenticated Attributes. This can undermine decisions that depend on trusted signed content. AWS states that customers using AWS services do not need to act; independently operated applications using AWS-LC should be assessed and upgraded.

Executive priority

Treat this as a high-priority integrity issue for applications using AWS-LC to trust PKCS7 signatures, especially when content arrives from untrusted networks. Inventory immediately and upgrade confirmed deployments promptly. Do not divert remediation resources for AWS-managed services, which AWS identifies as requiring no customer action.

Technical view

AWS-LC PKCS7_verify() contains improper signature validation for PKCS7 objects with Authenticated Attributes. An unauthenticated attacker can bypass verification where an application processes attacker-controlled objects through this path. The issue is CWE-347 with CVSS 4.0 score 8.7, reflecting network reachability, low complexity, no privileges or interaction, and high integrity impact.

Likely exposure

Exposure is limited to applications embedding or linking AWS-LC and passing untrusted PKCS7 objects with Authenticated Attributes to PKCS7_verify(). AWS service customers are unaffected according to AWS. The bundle does not clearly establish the complete vulnerable version range; it names 1.41.0 while also marking its default status unaffected.

Exploitation context

The CVSS assessment supports unauthenticated network exploitation when an exposed application processes attacker-controlled PKCS7 content. The bundle marks this CVE as absent from KEV and provides no cited evidence of active exploitation. Actual reachability depends on application data flows and use of the affected function.

Researcher notes

The core weakness is CWE-347 in Authenticated Attributes handling within PKCS7_verify(). Validate reachability and deployed library provenance before classifying exposure. The supplied version metadata is internally ambiguous, so avoid asserting a vulnerable range beyond vendor-confirmed applicability. No active exploitation is established by the provided evidence.

Mitigation direction

  • Inventory applications that directly or transitively include AWS-LC.
  • Upgrade affected application deployments to AWS-LC 1.69.0 as directed by AWS.
  • Prioritize internet-facing and trust-sensitive PKCS7 processing paths.
  • Consult the AWS advisory where version applicability remains uncertain.

Validation and detection

  • Confirm deployed artifacts use AWS-LC 1.69.0.
  • Identify code paths invoking PKCS7_verify() on externally supplied content.
  • Verify whether accepted PKCS7 objects contain Authenticated Attributes.
  • Regression-test that invalid or altered signatures are rejected.
  • Confirm AWS-service-only usage requires no customer remediation.
Prepared
Confidence
medium
Sources
6

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

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-347: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. 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 lookup
cve · low confidence lookup

CVE-2026-3338 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
High
CVSS
8.7 (4.0)
Known Exploited
No
Published

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

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.

3CVSS vectors
5Timeline events
2ADP providers
8Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: yesTechnical Impact: partial

CVSS vector scores

3 official scores

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
8.7CVSS 4.0HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N——AMZN
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N3.93.6AMZN
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N3.93.6redhat-SADP

Vulnerability scoring details

Base CVSS 4.0 score

8.7High
CVSS 4.0 vector shape for CVE-2026-3338Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Attack Requirements
NonePresent
Privileges Required
NoneLowHigh
User Interaction
NonePassiveActive
VS Confidentiality
HighLowNone
VS Integrity
HighLowNone
VS Availability
HighLowNone
SS Confidentiality
HighLowNone
SS Integrity
HighLowNone
SS Availability
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Made public.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
redhat-SADPaws-lc: AWS-LC: Signature bypass due to improper validation in PKCS7_verify()
other:Red Hat severity ratingcvssV3_1
  • 2026-03-02T22:01:12.080Z: Reported to Red Hat.
  • 2026-03-02T21:22:41.954Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
AWSAWS-LC1.41.0unaffected
Weakness

CWE details

CWE-347

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

CWE-347 · source CWE mapping

Improper Verification of Cryptographic Signature

Improper Verification of Cryptographic Signature represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs