EUVD-2026-62347Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Unauthenticated remote forgery bypasses signature checks (PR:N, C:H/I:H); AC:L as the highest-impact RSA-SHA1 case needs no special timing; A:N because impersonation does not affect availability.
Primary rating from Vendor (CPANSec).
CVSS VectorVendor: CPANSec
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
5DescriptionCVE.org
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.
AnalysisAI
Signature-verification bypass in the Net::OAuth Perl module before 0.33 lets a remote attacker forge valid OAuth requests for any consumer key and token by dictating which algorithm the Service Provider uses to check their signature. Because verify() resolves the signature-method class from the attacker-supplied signature_method parameter and offers no way to pin an expected method, a provider deployed on RSA-SHA1 (which holds only the consumer's public key) can be tricked into validating an HMAC-SHA1 signature against a placeholder/guessable consumer_secret. …
Unlock full vulnerability intelligence
- Risk assessment & exploitation conditions
- Attack chain visualization
- Remediation with exact patch versions
- Threat intelligence from 22 sources
- Personal watchlist & email alerts
Free forever · No credit card required
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires a Service Provider that uses Net::OAuth (before 0.33) to verify() incoming OAuth 1.0 messages without pinning the signature method - which is every pre-0.33 deployment, since no pinning mechanism existed. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N, C:H/I:H/A:H = 9.8) reflects unauthenticated, remote, low-complexity forgery, and the CWE-347 root cause and vendor advisory corroborate a genuine authentication-bypass. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An OAuth Service Provider runs Net::OAuth 0.32 configured for RSA-SHA1, holding only each Consumer's public key. An attacker crafts a protected-resource request with oauth_signature_method=HMAC-SHA1 and an HMAC signature computed over the non-secret placeholder consumer_secret, and submits it for any consumer key and token. … |
| Remediation | Upgrade to Vendor-released patch: Net::OAuth 0.33 (https://metacpan.org/release/RRWO/Net-OAuth-0.33/changes), which is a deliberate BREAKING change: verify() now croaks unless the verifying party explicitly states acceptable algorithms. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory all production systems using Net::OAuth Perl module and identify currently deployed versions. …
Sign in for detailed remediation steps and compensating controls.
Threat intelligence, references, and detailed analysis are available after sign-in.
More in Jwt Attack
View allWhy is Microsoft republishing a CVE from 2013? We are republishing CVE-2013-3900 in the Security Update Guide to update
Authentication bypass in SimpleHelp 5.5.15 and prior (plus 6.0 pre-release builds) allows remote unauthenticated attacke
Authentication bypass in Fortinet FortiOS, FortiProxy, and FortiSwitchManager allows unauthenticated remote attackers to
ruby-saml provides security assertion markup language (SAML) single sign-on (SSO) for Ruby. Rated critical severity (CVS
ruby-saml provides security assertion markup language (SAML) single sign-on (SSO) for Ruby. Rated critical severity (CVS
The package jsrsasign before 10.5.25 are vulnerable to Improper Verification of Cryptographic Signature when JWS or JWT
A library injection vulnerability exists in Microsoft Teams (work or school) 24046.2813.2770.1094 for macOS. Rated criti
A library injection vulnerability exists in the WebView.app helper app of Microsoft Teams (work or school) 24046.2813.27
A library injection vulnerability exists in the com.microsoft.teams2.modulehost.app helper app of Microsoft Teams (work
The Ruby SAML library is for implementing the client side of a SAML authorization. Rated critical severity (CVSS 9.8), t
cosign is a container signing and verification utility. Rated critical severity (CVSS 9.8), this vulnerability is remote
Biscuit is an authentication and authorization token for microservices architectures. Rated critical severity (CVSS 9.8)
Same technique Information Disclosure
View allShare
External POC / Exploit Code
Leaving vuln.today