CVE-2026-75509
joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to version
CVSS
6.5
Medium
EPSS
0.1%
p2
KEV
—
Exploit Today
1
0-100
Published: Aug 24, 2026 · Last modified: Oct 12, 2026 · CWE-290 · CWE-345
0.1%EPSS · 30 days0.1%
2026-09-262026-10-25
joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to version 1.7.3, JWTClaimsRegistry applies membership matching to list-valued iss and sub claims, allowing an array-valued iss that contains the expected issuer to pass an intended equality check and enabling issuer-validation bypass. This issue is fixed in version 1.7.3.
CVECVSSEPSSKEVRExploitTitleMod.
CVE-2026-1159339.9 CRI16.1%
——5Postiz signs its session, invitation and password reset tokens with one shared secret and without any marker of what a token is for. A route that refreshes the credentials of a browser-extension channel signed data taken from the request itself and stored the result where the requesting user can read it back. A user could therefore obtain a validly signed token containing any claims they choose, which the application accepts as a session, as an organization invitation with a chosen role, as a password reset or as an enterprise provisioning token.
A second, narrower route that creates team invitations signs extra fields from the request body in the same way.1dCVE-2026-1159377.5 HIG5.8%
——2The Mollie webhook endpoint accepts two independent, attacker-controlled parameters and never verifies that they belong together:
* commerceTransactionHash — selects which Craft Commerce transaction is completed
* id — selects which Mollie payment is queried for its status
An unauthenticated attacker holding any paid Mollie payment ID from the merchant’s account can pair it with any transaction hash.
Commerce queries Mollie, sees status: paid, and marks the target transaction successful for that transaction’s full
amount, regardless of how much was actually paid.2dCVE-2026-554597.4 HIG10.3%
——3The Goobi viewer is a web application that allows digitised material to be displayed in a web browser. From version 25.01 to before version 26.05, AuthenticationEndpoint.verifyOpenIdToken builds its verifier as JWT.require(algorithm).withIssuer(issuer).build() and does not enforce the aud claim during cryptographic validation. The aud check is performed manually afterwards via a single string-equality call, which only handles single-string aud values. In a multi-RP IdP setup, a token whose single-string aud matches the viewer's client ID but was issued for a different relying party passes the check and authenticates the attacker as the token's sub. This issue has been patched in version 26.05.2dCVE-2026-936295.3 MED18.8%
——6An organizer authentication vulnerability in Zimbra Collaboration Suite (ZCS) allows an unauthenticated email sender to insert calendar invitations attributed to another user. The email delivery path permits external invitations but does not verify that the message sender is authorized to use the iCalendar ORGANIZER identity. When automatic invitation insertion is enabled, a crafted REQUEST component creates an event containing attacker-selected meeting details and reminders under a forged organizer without recipient interaction. No corresponding event is created in the claimed organizer's calendar. ZCS 10.1.16 and 10.1.21 are affected.2dCVE-2026-936285.3 MED18.8%
——6An attendee authentication vulnerability in the email calendar processing of Zimbra Collaboration Suite (ZCS) allows an unauthenticated sender to forge another attendee's response to an existing meeting. Zimbra passes a null sender identity when processing iCalendar REPLY components, causing the attendee authorization filter to be skipped. An attacker who knows the meeting UID, organizer address and attendee address can send a non-outdated reply that changes the attendee's participation status in the organizer's calendar. The change occurs automatically during delivery without organizer or attendee interaction. ZCS 10.1.16 and 10.1.21 are affected.2dCVE-2026-936275.3 MED18.8%
——6An organizer authentication vulnerability in the email calendar processing of Zimbra Collaboration Suite (ZCS) allows an unauthenticated sender to cancel or modify an existing meeting in a recipient's calendar. Zimbra accepts iCalendar CANCEL and REQUEST components without verifying that the email sender is authorized to act as the supplied organizer. An attacker who knows the meeting UID and organizer address can supply a non-outdated sequence number to move the recipient's meeting to Trash or replace its details. Processing occurs automatically during email delivery without recipient interaction. ZCS 10.1.16 and 10.1.21 are affected.2d