WireGuard Easy Weak Token Generation Information Disclosure via OTL Route

published 2026-07-16 3 mo ago modified 2026-11-08 24 h ago also EUVD-2026-45013

cvss: 9.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 36%
public exploits: 0; none known

WireGuard Easy through 15.3.0, fixed in commit 66b292b, contains a cryptographically weak one-time link token generation vulnerability that allows unauthenticated network attackers to recover WireGuard peer credentials by brute-forcing a keyspace of at most 1000 candidate tokens per client ID, as the token is computed using CRC32 over a random value constrained to 0-999. Attackers can enumerate candidate tokens against the unauthenticated /cnf/:oneTimeLink route, which lacks rate limiting and does not validate token expiration, to obtain a peer's PrivateKey and PresharedKey and impersonate that peer on the VPN network.

Patch / fix

links 2

github.com/wg-easy/wg-easy@66b292b commit
github.com/wg-easy/wg-easy#2661 pull request

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: 3 mo ago (2026-07-18)

Exploit prediction

0.41% chance of exploitation in the next 30 days, higher than 36% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	9.0	CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:L/SA:N
CNA	3.1	9.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N
CNA	4.0	9.0	CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:L/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:X/V:X/RE:X/U:X

Affected products

wg-easy wg-easy

Classification

Weakness

CWE-338 Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
CWE-613 DEPRECATED: Insufficient Session Expiration

References

github.com /wg-easy/wg-easy/pull/2661
issue-tracking, patch
github.com /wg-easy/wg-easy/commit/66b292b11bde3664f05ffb016c8082665d261ded
patch
vulncheck.com /advisories/wireguard-easy-weak-token-generation-information-disclosure-via-otl-route
third-party-advisory

Sources

CVE List CVE-2026-63089
NVD CVE-2026-63089

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary