CVE-2026-72889 (GCVE-0-2026-72889)
Vulnerability from cvelistv5 – Published: 2026-08-19 07:20 – Updated: 2026-08-19 07:20
VLAI
EPSS
VEX
Title
Net::OAuth versions before 0.33 for Perl allow the sender to choose the signature algorithm in verify
Summary
Net::OAuth versions before 0.33 for Perl allow the sender to choose the signature algorithm in verify.
verify resolves the signature method class from the signature_method parameter of the incoming message. signature_method is required on every request, so the algorithm used to check a signature is chosen by whoever sent it, and nothing lets the verifying party pin the method instead. When a message names HMAC-SHA1 or HMAC-SHA256, the key is derived from consumer_secret and token_secret rather than from the key the provider deployed.
A provider deployed on RSA-SHA1 holds only the consumer public key, and RFC 5849 does not use consumer_secret for that method, so the required parameter is filled with a placeholder. A client that names HMAC-SHA1 instead has its signature checked against that placeholder, so a guessable one is enough to forge requests for any consumer key and token.
Severity
No CVSS data available.
CWE
Assigner
References
5 references
| URL | Tags |
|---|---|
| https://github.com/vurtdev/Net-OAuth/security/adv… | vendor-advisory |
| https://github.com/vurtdev/Net-OAuth/commit/c467a… | patch |
| https://metacpan.org/release/RRWO/Net-OAuth-0.33/… | release-notes |
| https://datatracker.ietf.org/doc/html/rfc5849#sec… | technical-description |
| https://datatracker.ietf.org/doc/html/rfc5849#sec… | technical-description |
{
"containers": {
"cna": {
"affected": [
{
"collectionURL": "https://cpan.org/modules",
"defaultStatus": "unaffected",
"modules": [
"Net::OAuth"
],
"packageName": "Net-OAuth",
"packageURL": "pkg:cpan/Net-OAuth",
"programFiles": [
"lib/Net/OAuth/Message.pm",
"lib/Net/OAuth/Request.pm"
],
"programRoutines": [
{
"name": "Net::OAuth::Message::verify"
},
{
"name": "Net::OAuth::Message::_signature_method_class"
},
{
"name": "Net::OAuth::Request::signature_key"
}
],
"repo": "https://github.com/vurtdev/Net-OAuth",
"versions": [
{
"lessThan": "0.33",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "Net::OAuth versions before 0.33 for Perl allow the sender to choose the signature algorithm in verify.\n\nverify resolves the signature method class from the signature_method parameter of the incoming message. signature_method is required on every request, so the algorithm used to check a signature is chosen by whoever sent it, and nothing lets the verifying party pin the method instead. When a message names HMAC-SHA1 or HMAC-SHA256, the key is derived from consumer_secret and token_secret rather than from the key the provider deployed.\n\nA provider deployed on RSA-SHA1 holds only the consumer public key, and RFC 5849 does not use consumer_secret for that method, so the required parameter is filled with a placeholder. A client that names HMAC-SHA1 instead has its signature checked against that placeholder, so a guessable one is enough to forge requests for any consumer key and token."
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-347",
"description": "CWE-347 Improper Verification of Cryptographic Signature",
"lang": "en",
"type": "CWE"
}
]
},
{
"descriptions": [
{
"cweId": "CWE-757",
"description": "CWE-757 Selection of Less-Secure Algorithm During Negotiation (\u0027Algorithm Downgrade\u0027)",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-19T07:20:09.095Z",
"orgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
"shortName": "CPANSec"
},
"references": [
{
"tags": [
"vendor-advisory"
],
"url": "https://github.com/vurtdev/Net-OAuth/security/advisories/GHSA-c8rm-g5cm-4pf5"
},
{
"tags": [
"patch"
],
"url": "https://github.com/vurtdev/Net-OAuth/commit/c467adf45c8d77ac4b92ad78b3eebf949252ba7f.patch"
},
{
"tags": [
"release-notes"
],
"url": "https://metacpan.org/release/RRWO/Net-OAuth-0.33/changes"
},
{
"tags": [
"technical-description"
],
"url": "https://datatracker.ietf.org/doc/html/rfc5849#section-3.4.2"
},
{
"tags": [
"technical-description"
],
"url": "https://datatracker.ietf.org/doc/html/rfc5849#section-3.4.3"
}
],
"solutions": [
{
"lang": "en",
"value": "Upgrade to Net-OAuth 0.33 or later."
}
],
"source": {
"discovery": "UNKNOWN"
},
"title": "Net::OAuth versions before 0.33 for Perl allow the sender to choose the signature algorithm in verify",
"x_generator": {
"engine": "cpansec-cna-tool 0.1"
}
}
},
"cveMetadata": {
"assignerOrgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
"assignerShortName": "CPANSec",
"cveId": "CVE-2026-72889",
"datePublished": "2026-08-19T07:20:09.095Z",
"dateReserved": "2026-08-10T15:44:58.172Z",
"dateUpdated": "2026-08-19T07:20:09.095Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"nvd": "{\"cve\":{\"id\":\"CVE-2026-72889\",\"sourceIdentifier\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\",\"published\":\"2026-08-19T08:17:13.833\",\"lastModified\":\"2026-08-19T08:17:13.833\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Net::OAuth versions before 0.33 for Perl allow the sender to choose the signature algorithm in verify.\\n\\nverify resolves the signature method class from the signature_method parameter of the incoming message. signature_method is required on every request, so the algorithm used to check a signature is chosen by whoever sent it, and nothing lets the verifying party pin the method instead. When a message names HMAC-SHA1 or HMAC-SHA256, the key is derived from consumer_secret and token_secret rather than from the key the provider deployed.\\n\\nA provider deployed on RSA-SHA1 holds only the consumer public key, and RFC 5849 does not use consumer_secret for that method, so the required parameter is filled with a placeholder. A client that names HMAC-SHA1 instead has its signature checked against that placeholder, so a guessable one is enough to forge requests for any consumer key and token.\"}],\"affected\":[{\"source\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\",\"affectedData\":[{\"defaultStatus\":\"unaffected\",\"collectionURL\":\"https://cpan.org/modules\",\"packageName\":\"Net-OAuth\",\"modules\":[\"Net::OAuth\"],\"programFiles\":[\"lib/Net/OAuth/Message.pm\",\"lib/Net/OAuth/Request.pm\"],\"programRoutines\":[{\"name\":\"Net::OAuth::Message::verify\"},{\"name\":\"Net::OAuth::Message::_signature_method_class\"},{\"name\":\"Net::OAuth::Request::signature_key\"}],\"repo\":\"https://github.com/vurtdev/Net-OAuth\",\"packageURL\":\"pkg:cpan/Net-OAuth\",\"versions\":[{\"version\":\"0\",\"lessThan\":\"0.33\",\"versionType\":\"custom\",\"status\":\"affected\"}]}]}],\"metrics\":{},\"weaknesses\":[{\"source\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-347\"},{\"lang\":\"en\",\"value\":\"CWE-757\"}]}],\"references\":[{\"url\":\"https://datatracker.ietf.org/doc/html/rfc5849#section-3.4.2\",\"source\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\"},{\"url\":\"https://datatracker.ietf.org/doc/html/rfc5849#section-3.4.3\",\"source\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\"},{\"url\":\"https://github.com/vurtdev/Net-OAuth/commit/c467adf45c8d77ac4b92ad78b3eebf949252ba7f.patch\",\"source\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\"},{\"url\":\"https://github.com/vurtdev/Net-OAuth/security/advisories/GHSA-c8rm-g5cm-4pf5\",\"source\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\"},{\"url\":\"https://metacpan.org/release/RRWO/Net-OAuth-0.33/changes\",\"source\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\"}]}}"
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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