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CVE-2026-25726 cloudreve CVE debrief

CVE-2026-25726 is a high-severity vulnerability in Cloudreve, a self-hosted file management and sharing system. The vulnerability stems from the use of a 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 stored 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, an attacker can predict the secret_key, 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.

Vendor
cloudreve
Product
Unknown
CVSS
HIGH 8.1
CISA KEV
Not listed in stored evidence
Original CVE published
2026-04-03
Original CVE updated
2026-07-24
Advisory published
2026-04-03
Advisory updated
2026-07-24

Who should care

Administrators and users of Cloudreve self-hosted file management and sharing systems should be aware of this vulnerability and take immediate action to update to version 4.13.0 or later. Security teams should prioritize patching and monitoring for potential exploitation.

Technical summary

The Cloudreve application uses a weak pseudo-random number generator (math/rand) seeded with time.Now().UnixNano() to generate critical security secrets. This allows an attacker to predict the secret_key and hash_id_salt by obtaining the administrator's account creation time and brute-forcing the seed. The vulnerability can be exploited to forge valid JSON Web Tokens (JWTs) for any user, leading to full account takeover and privilege escalation.

Defensive priority

High

Recommended defensive actions

  • Update Cloudreve to version 4.13.0 or later
  • Review and rotate existing secret keys and hash_id_salt
  • Monitor for potential exploitation attempts
  • Implement additional security measures, such as multi-factor authentication
  • Review system logs for suspicious activity
  • Conduct regular security audits
  • Implement a Web Application Firewall (WAF)

Evidence notes

The CVE record was published on 2026-04-03T20:16:02.263Z and has been modified on 2026-07-24T22:10:00.140Z. The NVD entry is currently Analyzed. The vulnerability has been patched in version 4.13.0. Evidence is limited to public sources and may not reflect all affected systems or potential attack vectors. Defenders should verify patch application and monitor for unusual activity. Additional information may be available through vendor advisories and security bulletins.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-25726 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-25726

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-25726 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-25726

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.