Improper Certificate Validation vulnerability in ex-aws exawssns (ExAws.SNS, ExAws.SNS.PublicKeyCache modules) allows Signature Spoofing by Improper Validation.
This vulnerability is associated with program files lib/exaws/sns.ex, lib/exaws/sns/publickeycache.ex and program routines 'Elixir.ExAws.SNS':verify_message/1, 'Elixir.ExAws.SNS.PublicKeyCache':get/1.
'Elixir.ExAws.SNS':verifymessage/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 verifymessage/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 exawssns: from 2.0.1 before 2.3.5.
{
"cna_assigner": "EEF",
"unresolved_ranges": [
{
"source": "AFFECTED_FIELD",
"extracted_events": [
{
"introduced": "a7ec21880943f4dac1d59bda557db0ffcd2b61fa"
},
{
"fixed": "1853d280b152d10384a1e21a22cf22152a60be48"
}
]
}
],
"cwe_ids": [
"CWE-295"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47074.json"
}