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TI-2026-74310 Aliases CVE-2026-105236

Erlang/OTP session resumption skips SNI client certificate checks

Priority LOW 28CWE-295Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
Present
Impact type
Spoofing
Confidentiality · integrity · availability
Low · Low · None
Fix status
Partial Red Hat: 1 fixed, 4 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-295.

Summary

Erlang/OTP from 18.0 before 27.3.4.19, 28.5.0.8 and 29.1.2 has an improper certificate validation flaw (CWE-295) in the ssl application. A TLS 1.2 session cached for one SNI name on a listener is resumed on another SNI name, and the resumption does not recheck the client certificate against the CA trusted for the requested name. A client holding a certificate trusted by one SNI name can authenticate to a second SNI name on the same listener when both names share a server certificate. TLS 1.3 is not affected.

Written with Claude Haiku 5.5 from the sources below · 2026-10-30

Description from the CNA

Improper Certificate Validation vulnerability in the ssl application in Erlang/OTP allows a client that holds a certificate trusted by one SNI virtual host to authenticate to a second SNI virtual host on the same listener by resuming its TLS 1.2 session there. A server that serves several SNI names from one listen socket through sni_fun or sni_hosts keeps one pre-TLS 1.3 session cache per listener and does not bind a cached session to the SNI name or client trust policy that established it. When an SNI option set switches to verify_peer without naming reuse_sessions, ssl_config:update_options/3 inherits the base listener's reuse_sessions value of true, so the default that disables reuse for client-authenticating servers does not apply. On an abbreviated handshake ssl_session:is_resumable/4 checks only that the cached session uses one of the current server certificates and carries some peer certificate, and never revalidates that certificate against the CA selected for the requested name. The names must share a server certificate, which is common with wildcard or multi-SAN certificates. TLS 1.3 does not use this cache and is not affected. This issue affects OTP from OTP 18.0 before OTP 27.3.4.19, OTP 28.5.0.8, and OTP 29.1.2, corresponding to ssl from 7.0 before 11.2.12.14, 11.6.0.7, and 11.7.8.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00357 29th percentileScored 2026-11-08
Fix Partial Red Hat: 1 advisoryRed Hat: 1 fixed, 4 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
ErlangOTP18.0 and later—No fix listedCNA
ErlangOTP7.0 and later—No fix listedCNA
  • OTP VendorErlang Affected 18.0 and later Fixed in — No fix listed CNA
  • OTP VendorErlang Affected 7.0 and later Fixed in — No fix listed CNA

CPE names CNA · 1

CPEVersionsRoleVendor
cpe:2.3:a:erlang:erlang\/otp:*:*:*:*:*:*:*:*——Erlang
  • cpe:2.3:a:erlang:erlang\/otp:*:*:*:*:*:*:*:* Versions — — ·Erlang

Remediation

Upgrade to OTP 27.3.4.19, OTP 28.5.0.8 or OTP 29.1.2, or to ssl 11.2.12.14, 11.6.0.7 or 11.7.8 on the matching branch. Red Hat fixes Red Hat Hardened Images in RHSA-2026:83217. The sources list no fixed version for Red Hat OpenStack Platform 13 (Queens), 16.2, 17.1 and 18.0.

Written with Claude Haiku 5.5 from the sources below · 2026-10-30

Red Hat 1 advisory

  • RHSA-2026:83217 Released 2026-10-14 · Red Hat rating Moderate
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images erlang27-27.3.4.19-0.1.hum1@aarch64, erlang27-27.3.4.19-0.1.hum1@s390x, erlang27-27.3.4.19-0.1.hum1@src +47

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat OpenStack Platform 13 (Queens)AffectedNo fix yet: Fix deferred
Red Hat OpenStack Platform 16.2AffectedNo fix yet: Fix deferred
Red Hat OpenStack Platform 17.1AffectedNo fix yet: Fix deferred
Red Hat OpenStack Platform 18.0AffectedNo fix yet: Fix deferred
Red Hat Hardened ImagesFixed RHSA-2026:83217

Timeline

  1. 2026-10-15 Threatist record created from CVE-2026-105236
  2. 2026-10-16 Priority changed: MEDIUM → LOW
  3. 2026-10-18 CISA SSVC decision points changed
  4. 2026-10-20 Fix available: RHSA-2026:83217 · Red Hat
  5. 2026-10-20 Fix available: Red Hat Hardened Images · Red Hat
  6. 2026-10-20 CVSS score added · Red Hat
  7. 2026-10-30 Affected versions changed · Red Hat

References

Patch 3

Advisory 1

Other 4

  • TI-2025-23504 Erlang/OTP SSH Vulnerable to Pre-Authentication RCE KEVCVSS 3.1CRITICAL 10.0
  • TI-2026-48954 httpd parks a request worker indefinitely on a malformed chunk size sent after the headers CVSS 4.0HIGH 8.7
  • TI-2023-26623 The SSH transport protocol with certain OpenSSH extensions, found in OpenSSH before 9.6… CVSS 3.1MEDIUM 5.9
  • TI-2026-71037 Path traversal in rebar3 via unvalidated dependency app names CVSS 4.0HIGH 7.5
  • TI-2024-36042 ssl fails to validate incorrect extened key usage CVSS 3.1MEDIUM 5.5
  • TI-2020-10791 Rebar3 versions 3.0.0-beta.3 to 3.13.2 are vulnerable to OS command injection via URL… CVSS 3.1CRITICAL 9.8
See all 80 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences