CVE-2026-47074

ex_aws_sns SigningCertURL not validated in verify_message/1

Published May 28, 2026 CVSS 4.0 · 8.7 High EPSS < 1% KEV · Not listed
Description
Improper Certificate Validation vulnerability in ex-aws ex_aws_sns (ExAws.SNS, ExAws.SNS.PublicKeyCache modules) allows Signature Spoofing by Improper Validation.

This vulnerability is associated with program files lib/ex_aws/sns.ex, lib/ex_aws/sns/public_key_cache.ex and program routines 'Elixir.ExAws.SNS':verify_message/1, 'Elixir.ExAws.SNS.PublicKeyCache':get/1.

'Elixir.ExAws.SNS':verify_message/1 fetches the signing certificate from the SigningCertURL field of the incoming SNS message without validating that the URL uses HTTPS or that the host matches an AWS-owned SNS certificate domain. An unauthenticated attacker who can POST to an endpoint that calls verify_message/1 can supply an attacker-controlled SigningCertURL, sign a forged SNS message with their own key, and cause the function to return :ok, completely bypassing SNS signature verification.

This issue affects ex_aws_sns: from 2.0.1 before 2.3.5.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-jq4m-q6p2-8gwc Hackney: Per-chunk timeout with unbounded body accumulation enables slow-drip OOM
Github GHSA Github GHSA GHSA-8jgf-23q5-x7xx ex_aws_sns: Trusted-attacker `SigningCertURL` permits complete SNS signature bypass
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Improper Certificate Validation vulnerability in ex-aws ex_aws_sns (ExAws.SNS, ExAws.SNS.PublicKeyCache modules) allows Signature Spoofing by Improper Validation. This vulnerability is associated with program files lib/ex_aws/sns.ex, lib/ex_aws/sns/public_key_cache.ex and program routines 'Elixir.ExAws.SNS':verify_message/1, 'Elixir.ExAws.SNS.PublicKeyCache':get/1. 'Elixir.ExAws.SNS':verify_message/1 fetches the signing certificate from the SigningCertURL field of the incoming SNS message without validating that the URL uses HTTPS or that the host matches an AWS-owned SNS certificate domain. An unauthenticated attacker who can POST to an endpoint that calls verify_message/1 can supply an attacker-controlled SigningCertURL, sign a forged SNS message with their own key, and cause the function to return :ok, completely bypassing SNS signature verification. This issue affects ex_aws_sns: from 2.0.1 before 2.3.5.
Title ex_aws_sns SigningCertURL not validated in verify_message/1
First Time appeared Ex Aws Sns Project
Ex Aws Sns Project ex Aws Sns
Weaknesses CWE-295
CPEs cpe:2.3:a:ex_aws_sns_project:ex_aws_sns:*:*:*:*:*:*:*:*
Vendors & Products Ex Aws Sns Project
Ex Aws Sns Project ex Aws Sns
References
Metrics cvssV4_0

{'score': 8.7, '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
EEF
Published
Updated
May 29, 2026, 4:40 AM
Reserved
May 18, 2026, 5:28 PM
Status
Deferred
Published
May 28, 2026, 10:16 AM
Modified
Oct 26, 2026, 11:10 AM