VulnerabilityDeferred

CVE-2026-68554

Prior to 4.15.0, an on-path attacker can append attributes after MESSAGE-INTEGRITY to an authenticated STUN request on plain UDP or TCP, adjust the STUN header length, and recompute the unkeyed FINGERPRINT while the original HMAC remains valid because…

LOW 2.3EPSS 0.25%

Does this matter?

Lower severity and a low EPSS score (0.25%). Track it; it rarely justifies an emergency change on its own.

Description

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.15.0, an on-path attacker can append attributes after MESSAGE-INTEGRITY to an authenticated STUN request on plain UDP or TCP, adjust the STUN header length, and recompute the unkeyed FINGERPRINT while the original HMAC remains valid because it covers only the message prefix. Server-side parsing in src/server/ns_turn_server.c continues past MESSAGE-INTEGRITY through handle_turn_allocate(), handle_turn_create_permission(), handle_turn_refresh(), and handle_turn_command(), allowing trailing LIFETIME, XOR-PEER-ADDRESS, or ORIGIN attributes to override allocation lifetime, inject a permission, or bypass the origin check. TLS and DTLS deployments prevent this in-transit modification. This issue is fixed in version 4.15.0.

CVSS 4.0: 2.3 LOWCVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/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/M
EPSS: 0.25% probability · 16th percentile
CISA KEV: Not listed
Weakness: CWE-345, CWE-924
Source: security-advisories@github.com

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.