rustls 0.23.44 and 0.23.45 ECH Rejection Application Data Disclosure
Summary
| CVE | CVE-2026-123612 |
|---|---|
| State | PUBLISHED |
| Assigner | VulnCheck |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-11-08 02:16:56 UTC |
| Updated | 2026-11-08 02:16:56 UTC |
| Description | rustls 0.23.44 and 0.23.45 contain an information disclosure vulnerability that sends application data buffered before the handshake completes to the client-facing server when Encrypted Client Hello is rejected. Because start_traffic() queues plaintext from ClientConnection::writer() before sending the ech_required alert, the authenticated public_name server receives data intended for the inner server. |
Risk And Classification
Primary CVSS: v4.0 4.6 MEDIUM from [email protected]
CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:L/VI:N/VA:N/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-696 | CWE-696 Incorrect Behavior Order
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 4.6 | MEDIUM | CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/C... |
| 4.0 | CNA | CVSS | 4.6 | MEDIUM | CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N |
| 3.1 | [email protected] | Primary | 2.3 | LOW | CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N |
| 3.1 | CNA | CVSS | 2.3 | LOW | CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N |
CVSS v4.0 Breakdown
Attack Vector
LocalAttack Complexity
LowAttack Requirements
NonePrivileges Required
HighUser Interaction
NoneConfidentiality
LowIntegrity
NoneAvailability
NoneSub Conf.
NoneSub Integrity
NoneSub Availability
NoneCVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:L/VI:N/VA:N/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
LocalAttack Complexity
LowPrivileges Required
HighUser Interaction
NoneScope
UnchangedConfidentiality
LowIntegrity
NoneAvailability
NoneCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N
Vendor Declared Affected Products
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| www.vulncheck.com/advisories/rustls-0.23.44-and-0.23.45-ech-rejection-applicati... | [email protected] | www.vulncheck.com | |
| github.com/rustls/rustls/security/advisories/GHSA-vp88-798v-h67f | [email protected] | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.