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Fencer Vulns
high 8.1

CVE-2026-25726 json

Cloudreve is vulnerable to Account Takeover via Weak Cryptographic Token Generation (Insecure PRNG Seeding)

published 2026-03-31 7 mo ago modified 2026-07-24 3 mo ago also EUVD-2026-18833 , GHSA-f8xp-wvcx-p6f4 , GO-2026-5350

cvss
8.1
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 33%
public exploits
0
none known

Summary

Cloudreve is a self-hosted file management and sharing system. Prior to version 4.13.0, the application uses the weak pseudo-random number generator math/rand seeded with time.Now().UnixNano() to generate critical security secrets, including the secret_key, and hash_id_salt. These secrets are generated upon first startup and persisted in the database. An attacker can exploit this by obtaining the administrator's account creation time (via public API endpoints) to narrow the search window for the PRNG seed, and use known hashid to validate the seed. By brute-forcing the seed (demonstrated to take <3 hours on general consumer PC), an attacker can predict the secret_key. This allows them to forge valid JSON Web Tokens (JWTs) for any user, including administrators, leading to full account takeover and privilege escalation. This issue has been patched in version 4.13.0.

Patch / fix

  • go github.com/cloudreve/Cloudreve/v4 4.0.0-20260205113604-ec9fdd33bc54
  • cloudreve cloudreve 4.13.0
  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
7 mo ago

Exploit prediction

0.39% chance of exploitation in the next 30 days, higher than 33% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
GitHub 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
go github.com/cloudreve/Cloudreve/v4
<4.0.0-20260205113604-ec9fdd33bc54
4.0.0-20260205113604-ec9fdd33bc54
go github.com/cloudreve/Cloudreve
all versions
 no fix listed
go github.com/cloudreve/Cloudreve/v3
all versions
 no fix listed

Affected products

  • cloudreve cloudreve

Classification

Weakness
  • CWE-338 Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

References

Sources

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.