← Vulnerability feed

Vulnerability record · CVE-2026-82454 · published 29 August 2026

CVE-2026-82454: Improper verification of cryptographic signature vulnerability

The Omnivore API (packages/api) before the fix in commit abf53d6 contains an authentication bypass in Apple sign-in token verification. The decodeAppleToken function extracted the 'alg' field from the attacker-supplied JWT header and passed it as the sole allowed algorithm to jwt.verify(). Using jsonwebtoken v8 (which does not validate key/algorithm compatibility), an attacker can set alg=HS256 and sign a forged token using Apple's publicly available RSA public key as the HMAC secret, bypassing signature verification and impersonating any Apple-linked account.

9.3 CVSS 4.0 Critical EPSS 0.39% · top 70.0% CWE-347 · Improper verification of cryptographic signature Deferred
9.3CVSS 4.0 base score
0.39%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
4References
24 Sep 2026Last modified by NVD

Description

The Omnivore API (packages/api) before the fix in commit abf53d6 contains an authentication bypass in Apple sign-in token verification. The decodeAppleToken function extracted the 'alg' field from the attacker-supplied JWT header and passed it as the sole allowed algorithm to jwt.verify(). Using jsonwebtoken v8 (which does not validate key/algorithm compatibility), an attacker can set alg=HS256 and sign a forged token using Apple's publicly available RSA public key as the HMAC secret, bypassing signature verification and impersonating any Apple-linked account.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

References

LinkTags
https://github.com/omnivore-app/omnivore
https://github.com/omnivore-app/omnivore/commit/abf53d6508755d3d22a994e28e370a9193ea977a
https://github.com/omnivore-app/omnivore/pull/4652
https://www.vulncheck.com/advisories/omnivore-before-android-0.227.0-authentication-bypass-via-apple-sign-in

Track CVE-2026-82454 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

10.0CVE-2026-5430Wso2 api control plane improper verification of cryptographic signature vulnerabilityThe JWT authentication mechanism accepts tokens signed with algorithms other than those explicitly configured or supported. This allows an attacker t…KEVEPSS 0.59%9.5CVE-2026-48558SimpleHelp OIDC authentication bypass via unverified token signatureSimpleHelp 5.5.15 and earlier and 6.0 pre-release versions accept OIDC identity tokens without verifying their cryptographic signature. When OIDC is …KEVEPSS 5.7%analysed9.8CVE-2025-59718Fortinet FortiOS/FortiProxy SAML signature check bypass in FortiCloud SSOFortiOS, FortiProxy and FortiSwitchManager fail to properly verify the cryptographic signature of SAML responses used for FortiCloud SSO login. An un…KEVEPSS 68%analysed4.6CVE-2025-47827IGEL OS Secure Boot bypass via improper signature verificationIGEL OS before version 11 fails to properly verify a cryptographic signature in the igel-flash-driver module, allowing Secure Boot to be bypassed. A …KEVEPSS 4.9%analysed10.0CVE-2020-2021PAN-OS SAML signature verification bypass allows authentication bypassPAN-OS fails to properly verify SAML signatures when SAML authentication is enabled and the 'Validate Identity Provider Certificate' option is unchec…KEVEPSS 4.4%analysed5.5CVE-2013-3900Windows WinVerifyTrust Authenticode signature verification RCECVE-2013-3900 is a remote code execution flaw in how the Windows WinVerifyTrust function verifies Authenticode signatures on portable executable file…KEVEPSS 45%analysed7.8CVE-2020-1464Windows file signature validation spoofing allows loading of improperly signed filesWindows incorrectly validates file signatures, so a crafted file can be treated as properly signed. This lets an attacker bypass the security feature…KEVEPSS 39%analysed

Source: NIST National Vulnerability Database (record CVE-2026-82454), CISA KEV, FIRST EPSS (scores of 2026-09-28). This page is refreshed as NVD updates the record.