November 14, 2026

CVE Watchtower

CVE-2026-123612rustls rustls

NVD

Vulnerability Summary

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.
Severity Level
MEDIUM(4.6)
Published Date
Nov 8, 2026
Last Modified
Nov 12, 2026
Exploitation Status
No confirmed exploitation yet
EPSS Score (30-Day)
0.11%Probability
Root Weakness (CWE)
CWE-696 ↗
See the MITRE CWE entry for the full definition of this weakness.
CVSS v4.0 Base Metrics — Score 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
Attack VectorLocal
Attack ComplexityLow
Attack RequirementsNone
Privileges RequiredHigh
User InteractionNone
Confidentiality (Vulnerable System)Low
Integrity (Vulnerable System)None
Availability (Vulnerable System)None
Confidentiality (Subsequent System)None
Integrity (Subsequent System)None
Availability (Subsequent System)None
Show CVSS v3.x metrics (score 2.3)
CVSS v3.1 Base Metrics — Score 2.3 (LOW)
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N
Attack VectorLocal
Attack ComplexityLow
Privileges RequiredHigh
User InteractionNone
ScopeUnchanged
ConfidentialityLow
IntegrityNone
AvailabilityNone

Affected & Patched Versions

Affected Versions
  • rustls rustls >= 0.23.44 and < 0.23.46
Patched Versions
  • rustls rustls 0.23.46

What to do

Fix it during your normal patch cycle. No exploitation is confirmed yet.

  1. Check whether you run rustls rustls and which version.
  2. Update to a patched version listed above, then confirm the new version.

Timeline

  • Nov 8, 2026Published
  • Nov 12, 2026Record last modified

Score, severity and exploitation changes are tracked from the day Watchtower started logging them.

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External References

Data last checked: Nov 14, 2026 02:13 UTC