CVE-2026-121553: cotonti · PRNG
Affects cotontiSource CVE Database V5
Not known to be exploited · CVSS 6.3 Medium.
Data as of 3 Nov 2026, 15:43 UTC
Thin evidence
One scorer or none| CNA (VulnCheck) | CVSS 4.0 | 6.3 |
|---|---|---|
| CNA (VulnCheck) | CVSS 3.1 | 4.8 |
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 3 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 3 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| cotonticotonti | Affected
| Fixed in– |
Packagistcotontipkg:composer/cotontiOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Until a fix is available, consider implementing additional verification controls or replacing the token generation mechanism with a cryptographically secure PRNG to prevent token prediction.
Description
Cotonti versions up to 1.0.0 use a cryptographically weak pseudo-random number generator (PRNG) to create registration and email-change validation tokens. The tokens are generated using md5(microtime()), which can be predicted by attackers who derive the generation time from the HTTP Date header. This allows attackers to bypass email-ownership verification by computing candidate tokens offline and submitting them to the validation handler, enabling unauthorized account activation or email confirmation.
References
- github.com/Cotonti/Cotonti/issues/1904 (opens in a new tab)
- github.com/Cotonti/Cotonti (opens in a new tab)
- github.com/Cotonti/Cotonti/blob/1.0.0/modules/users/inc/users.functions.php (opens in a new tab)
- github.com/Cotonti/Cotonti/blob/1.0.0/modules/users/inc/users.profile.php (opens in a new tab)
- github.com/Cotonti/Cotonti/blob/1.0.0/modules/users/inc/users.register.php (opens in a new tab)
- github.com/Cotonti/Cotonti/pull/1905 (opens in a new tab)
- vulncheck.com/advisories/cotonti-through-1.0.0-predictable-validation-tokens-via-md5-microtime (opens in a new tab)