CVE-2026-3338Network attack vector

Integrity bypass via malformed authenticated attributes

Published Mar 2, 2026 · Updated Mar 2, 2026

Improper signature validation in AWS-LC 1.41.0 through 1.68.0 allows remote attackers to bypass content integrity via crafted PKCS7 objects. PKCS7_verify() treated a -1 authenticated-attribute encoding error as success because its caller rejected only a zero return value. Attackers can alter content and its digest, then add a malformed zero-length OID, when an application verifies attacker-controlled PKCS7 data.

CVSS severity8.7
High
EPSS probability0.78%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper signature validation in AWS-LC 1.41.0 through 1.68.0 allows remote attackers to bypass content integrity via crafted PKCS7 objects. PKCS7_verify() treated a -1 authenticated-attribute encoding error as success because its caller rejected only a zero return value. Attackers can alter content and its digest, then add a malformed zero-length OID, when an application verifies attacker-controlled PKCS7 data.

The record

CVE
CVE-2026-3338
Published
Mar 2, 2026
Updated
Mar 2, 2026
Vendor
Amazon Web Services
Product
AWS-LC
Classifications
CWE-347
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 2, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 2, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.41.0 <1.69.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Amazon Web Services · AWS-LCversion=1.41.0 <1.69.0

Published CVSS scores

8.7AmazonCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
7.5AmazonCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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