Nixpkgs security tracker

Permalink CVE-2026-42553

7.1 HIGH

CVSS version (CVSS): 4.0
Attack Vector (AV): Network (N)
Attack Complexity (AC): Low (L)
Attack Requirement (AT): None (N)
Privileges Required (PR): Low (L)
User Interaction (UI): None (N)
Vulnerable System Impact Confidentiality (VC): High (H)
Vulnerable System Impact Integrity (VI): None (N)
Vulnerable System Impact Availability (VA): None (N)
Subsequent System Impact Confidentiality (SC): None (N)
Subsequent System Impact Integrity (SI): None (N)
Subsequent System Impact Availability (SA): None (N)
Modified Attack Vector (MAV): Network (N)
Modified Attack Complexity (MAC): Low (L)
Modified Attack Requirement (MAT): None (N)
Modified Privileges Required (MPR): Low (L)
Modified User Interaction (MUI): None (N)
Modified Vulnerable System Impact Confidentiality (MVC): High (H)
Modified Vulnerable System Impact Integrity (MVI): None (N)
Modified Vulnerable System Impact Availability (MVA): None (N)
Modified Subsequent System Impact Confidentiality (MSC): Negligible (N)
Modified Subsequent System Impact Integrity (MSI): Negligible (N)
Modified Subsequent System Impact Availability (MSA): Negligible (N)
Safety (S): Not Defined (X)
Automatable (AU): Not Defined (X)
Recovery (R): Not Defined (X)
Value Density (V): Not Defined (X)
Vulnerability Response Effort (RE): Not Defined (X)
Provider Urgency (U): Not Defined (X)
Confidentiality Req. (CR): Not Defined (X)
Integrity Req. (IR): Not Defined (X)
Availability Req. (AR): Not Defined (X)
Exploit Maturity (E): Not Defined (X)

created 4 days, 14 hours ago Activity log

Created suggestion 4 days, 14 hours ago

Cinny: Access token disclosure via invalidated emoji pack avatar URL in service worker

Cinny is a Matrix client. Prior to 4.10.3, A remote authenticated attacker who shares a room with a victim and has permissions to create room emotes (for example in a DM) can cause the victim's client to send their Matrix access token to an attacker-controlled server. This occurs when the victim opens the emoji or sticker picker for the room containing a malicious emote pack. This is caused by an incorrect fallback in EmojiBoard that uses untrusted pack.meta.avatar (user-controlled) without converting/validating it as an MXC URL, allowing arbitrary HTTP(S) URLs to be used. Also, the service worker attaching the user's Authorization bearer token to all outbound GET requests whose URL contains /_matrix/client/v1/media/download or /_matrix/client/v1/media/thumbnail without verifying the request host matches the configured homeserver origin. An attacker-controlled URL containing those path fragments and permissive CORS will receive the victim's Authorization header (access token). This vulnerability is fixed in 4.10.3.