LiveActive security incident?Get immediate response
CVE Record

CVE-2026-3336: PKCS7_verify Certificate Chain Validation Bypass in AWS-LC

Improper certificate validation in PKCS7_verify() in AWS-LC allows an unauthenticated user to bypass certificate chain verification when processing PKCS7 objects with multiple signers, except the final signer. 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

AWS-LC has a certificate-checking flaw in PKCS7_verify(). In some multi-signer PKCS7 cases, an unauthenticated attacker could bypass certificate chain validation for signers other than the final signer. AWS says AWS service customers do not need action, but applications directly using AWS-LC should upgrade.

Executive priority

Treat this as a high-priority dependency remediation for products that directly use AWS-LC. It can undermine trust decisions in certificate validation, which may affect integrity-sensitive workflows. AWS-hosted service consumption alone is not identified as requiring customer action.

Technical view

CVE-2026-3336 is CWE-295 improper certificate validation in AWS-LC PKCS7_verify(). The issue affects processing of PKCS7 objects with multiple signers, allowing chain validation bypass except for the final signer. CVSS 4.0 is 8.7 high, with network attack vector, low complexity, no privileges, and no user interaction.

Likely exposure

Exposure is most likely in applications or packaged products that directly use affected AWS-LC versions for PKCS7 verification. The source bundle names AWS-LC 1.41.0 and states applications using AWS-LC should upgrade to 1.69.0. AWS service customers are stated as not needing action.

Exploitation context

The provided sources do not show CISA KEV listing or active exploitation. The CVSS vector indicates remote, unauthenticated reachability with low complexity, but the bundle does not provide exploit availability, proof-of-concept status, or weaponized details.

Researcher notes

Focus review on multi-signer PKCS7 validation behavior and whether non-final signer chains are accepted incorrectly. The source bundle does not establish affected downstream products beyond AWS-LC references, nor active exploitation. Avoid assuming TLS exposure unless PKCS7_verify() use is confirmed.

Mitigation direction

  • Upgrade AWS-LC to version 1.69.0 or later.
  • Apply vendor-packaged fixes, including relevant Red Hat errata where applicable.
  • Inventory applications and products that directly embed or link AWS-LC.
  • Prioritize systems that parse PKCS7 data from untrusted sources.
  • Monitor AWS-LC, AWS, and distribution advisories for follow-up guidance.

Validation and detection

  • Check SBOMs and dependency manifests for AWS-LC usage and versions.
  • Confirm deployed binaries use AWS-LC 1.69.0 or a vendor-fixed build.
  • Identify code paths that call PKCS7_verify() on externally supplied PKCS7 objects.
  • Review package manager advisories for Red Hat or other downstream fixes.
  • Document AWS service-only usage separately, since AWS says no customer action is needed.
Prepared
Confidence
high
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

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-295: 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-2026-3336 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-2026-3336Attack 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: Certificate validation bypass via improper handling of PKCS7 objects
other:Red Hat severity ratingcvssV3_1
  • 2026-03-02T22:01:15.917Z: Reported to Red Hat.
  • 2026-03-02T21:15:16.709Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
AWSAWS-LC1.41.0unaffected
Weakness

CWE details

CWE-295

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

CWE-295 · source CWE mapping

Improper Certificate Validation

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

Open CWE intelligenceSame-CWE CVEs