PatchTheCVECVE-2026-121553: Cotonti through 1.0.0 generates registration and email-change validation tokens with md5(microtime()), allowin
CVE-2026-121553 is a medium-severity flaw (CVSS 4.8) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
Cotonti through 1.0.0 generates registration and email-change validation tokens with md5(microtime()), allowing attackers to bypass email-ownership verification by predicting tokens. Attackers can derive the generation time from the HTTP Date header and compute candidate tokens offline. They then submit these tokens to the users.register.php validate handler to activate accounts or confirm email addresses they do not control.
Why this priority
- Remotely exploitable, no login, no user action
No fix is published yet: follow the downgrade or mitigation steps.
Risk facts
| CVSS score | 4.8 (Medium) |
| Attack vector | Network (remote) |
| Attack complexity | High |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | n/a |
| CISA exploited list | No |
| Weakness | CWE-338 |
| Published | 2026-11-03 |
| Last modified | 2026-11-03 |
Last updated 2026-11-03 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Timeline
- Published CVE record published
- Updated Record last modified
Advisories and coverage
Research and news
- VulDB Recent Entries: CVE-2026-121553 | Cotonti up to 1.0.0 users.register.php microtime random values 2026-11-03
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-121553?
No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.
Is CVE-2026-121553 being exploited?
CVE-2026-121553 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-121553 affect?
CVE-2026-121553 affects affected software. Severity is medium (CVSS 4.8). Cotonti through 1.0.0 generates registration and email-change validation tokens with md5(microtime()), allowing attackers to bypass email-ownership verification by predicting tokens. Attackers can derive the generation time from the HTTP Da
How urgent is CVE-2026-121553?
Priority 22/100. Remotely exploitable, no login, no user action