Cotonti through 1.0.0 Predictable Validation Tokens via md5(microtime())
Summary
| CVE | CVE-2026-121553 |
|---|---|
| State | PUBLISHED |
| Assigner | VulnCheck |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-11-03 16:17:27 UTC |
| Updated | 2026-11-03 16:17:27 UTC |
| Description | 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. |
Risk And Classification
Primary CVSS: v4.0 6.3 MEDIUM from [email protected]
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/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
Problem Types: CWE-338 | CWE-338 Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 6.3 | MEDIUM | CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/C... |
| 4.0 | CNA | CVSS | 6.3 | MEDIUM | CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N |
| 3.1 | [email protected] | Primary | 4.8 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L |
| 3.1 | CNA | CVSS | 4.8 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
HighAttack Requirements
NonePrivileges Required
NoneUser Interaction
NoneConfidentiality
NoneIntegrity
LowAvailability
LowSub Conf.
NoneSub Integrity
NoneSub Availability
NoneCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/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
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
HighPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
LowAvailability
LowCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L
Vendor Declared Affected Products
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/Cotonti/Cotonti | [email protected] | github.com | |
| github.com/Cotonti/Cotonti/pull/1905 | [email protected] | github.com | |
| github.com/Cotonti/Cotonti/issues/1904 | [email protected] | github.com | |
| github.com/Cotonti/Cotonti/blob/1.0.0/modules/users/inc/users.profile.php | [email protected] | github.com | |
| github.com/Cotonti/Cotonti/blob/1.0.0/modules/users/inc/users.functions.php | [email protected] | github.com | |
| github.com/Cotonti/Cotonti/blob/1.0.0/modules/users/inc/users.register.php | [email protected] | github.com | |
| www.vulncheck.com/advisories/cotonti-through-1.0.0-predictable-validation-token... | [email protected] | www.vulncheck.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Sun Kimsroul (en)
There are currently no legacy QID mappings associated with this CVE.