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NVD / CVE Program· CNA EEF

CVE-2026-89422: TLS 1.3 client skips server authentication when ServerHello carries an unsolicited pre_shared_key extension

Noroxi assessment

Priority: Monitor (action score 37/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.46% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Erlang OTP 11.2.12.13, 11.6.0.6, 11.7.7; azl3 erlang 26.2.5.21-6 on Azure Linux 3.0 26.2.5.21-7.

Low priority for now. Upgrade to Erlang OTP 11.2.12.13, 11.6.0.6, 11.7.7; azl3 erlang 26.2.5.21-6 on Azure Linux 3.0 26.2.5.21-7 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Key Exchange without Entity Authentication vulnerability in Erlang/OTP ssl allows a peer that answers a TLS 1.3 client connection to impersonate the intended server. A pre_shared_key extension in the ServerHello that the client never offered causes the client to complete the handshake without validating the server's certificate, so ssl:connect returns {ok, Socket} against a peer holding no certificate, no private key and no prior session. tls_client_connection_1_3:handle_server_hello/2 passes the received extension to tls_gen_connection_1_3:handle_resumption/2, which sets resumption = true on its mere presence without checking that the client offered a PSK. tls_handshake_1_3:get_pre_shared_key/4 meanwhile falls back to the all-zero "no PSK" value and keys the handshake with the ordinary non-PSK schedule, so the attacker's own ephemeral key suffices. The resumption flag then routes maybe_resumption/1 straight to wait_finished, skipping the certificate-handling states, so certificate path validation, verify_fun, hostname verification, partial_chain, CRL checking and OCSP stapling are all bypassed. The default client configuration is affected; clients restricted to TLS 1.2 are not. This issue affects OTP from OTP 22.2 before OTP 27.3.4.18, OTP 28.5.0.7, and OTP 29.1.1, corresponding to ssl from 9.5 before 11.2.12.13, 11.6.0.6, and 11.7.7.

CriticalCVSS 9.3 · v4.0—No exploit Fix available
Published
Sep 22, 2026
Updated
Sep 22, 2026
EPSS
0.4% · 39th percentile

Report tools

JSON

Action score

37

Monitor

Low priority for now.

CVSS
37 / 40 · 9.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · EEF
9.3
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (EEF). Independent of NVD's CPE analysis and usually ahead of it.

  • Erlang OTP

    • 22.2 and lateraffected · otpfixed in 27.3.4.18, 28.5.0.7, 29.1.1
    • 9.5 and lateraffected · otpfixed in 11.2.12.13, 11.6.0.6, 11.7.7
    • 21b8a1b0ad0adf200682b3854bc50114ab2b8c62 and lateraffected · gitfixed in afec5156361bb50d3607c7c1a453c19b9149b324, 98c66c858113949c4262d26cd7d426c4b09d2b35, fd1d9d07fc92ec0d59f96dfb66182195882bb7dd

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12erlangfrom 0—
Debian:13erlangbefore 1:27.3.4.1+dfsg-1+deb13u41:27.3.4.1+dfsg-1+deb13u4
Debian:14erlangbefore 1:29.1.1+dfsg-11:29.1.1+dfsg-1

Same product

erlang: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74835inets,httpd: Memory Exhaustion via Unenforced max_body_size During Chunked Body Reception
    34Monitor
  • CVE-2026-71380httpd applies no timeout while receiving a request body, parking a worker on a stalled client
    34Monitor
  • CVE-2026-70399httpd does not enforce the documented default max_clients connection limit
    34Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-65634Sep 22, 2026 · Superlinear CPU denial of service in Erlang/OTP ASN.1 OBJECT IDENTIFIER decoder
    32Monitor
  • ← EarlierCVE-2026-68956Sep 22, 2026 · SSH daemon allocates unbounded idle session channels, bypassing max_channels
    28Monitor
  • Later →CVE-2026-105236Oct 14, 2026 · TLS 1.2 session resumption in ssl crosses SNI virtual-host client-certificate trust boundaries
    25Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Erlang OTP11.2.12.13Vendor (CNA)
Erlang OTP11.6.0.6Vendor (CNA)
Erlang OTP11.7.7Vendor (CNA)
Erlang OTP27.3.4.18Vendor (CNA)
Erlang OTP28.5.0.7Vendor (CNA)
Erlang OTP29.1.1Vendor (CNA)
Erlang OTP98c66c858113949c4262d26cd7d426c4b09d2b35Vendor (CNA)
Erlang OTPafec5156361bb50d3607c7c1a453c19b9149b324Vendor (CNA)
Erlang OTPfd1d9d07fc92ec0d59f96dfb66182195882bb7ddVendor (CNA)
azl3 erlang 26.2.5.21-6 on Azure Linux 3.026.2.5.21-7 · Release NotesMicrosoft (MSRC)
debian:erlang1:27.3.4.1+dfsg-1+deb13u4 · Debian:13Package registry (OSV)
debian:erlang1:29.1.1+dfsg-1 · Debian:14Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
X

Weakness class (CWE)

CWE-322 · Key Exchange without Entity Authentication

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records