CVE-2026-54891Network attack vector

Blind plaintext injection via missing client-state checks

Published Jul 2, 2026 · Updated Jul 2, 2026

Plaintext injection in Erlang/OTP ssl allows attackers to inject unauthenticated data into TLS clients during handshakes. The tls_gen_connection:handle_protocol_record/3 function omits client-role rejection of pre-handshake APPLICATION_DATA, buffers those plaintext records, and delivers them after authentication completes. Exploitation requires a network position during the handshake, and the attacker gains only blind byte injection without observing responses or controlling the connection.

CVSS severity6.3
Medium
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Plaintext injection in Erlang/OTP ssl allows attackers to inject unauthenticated data into TLS clients during handshakes. The tls_gen_connection:handle_protocol_record/3 function omits client-role rejection of pre-handshake APPLICATION_DATA, buffers those plaintext records, and delivers them after authentication completes. Exploitation requires a network position during the handshake, and the attacker gains only blind byte injection without observing responses or controlling the connection.

The record

CVE
CVE-2026-54891
Published
Jul 2, 2026
Updated
Jul 2, 2026
Vendor
Erlang
Product
Erlang/OTP
Classifications
CWE-924, CAPEC-94, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 2, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 2, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=17.0 <* changes=[{"at":"29.0.3","status":"unaffected"},{"at":"28.5.0.3","status":"unaffected"},{"at":"27.3.4.14","status":"unaffected"}]
  2. Affected versionversion=5.3.4 <* changes=[{"at":"11.7.3","status":"unaffected"},{"at":"11.6.0.3","status":"unaffected"},{"at":"11.2.12.10","status":"unaffected"}]
  3. Affected versionversion=84adefa331c4159d432d22840663c38f155cd4c1 <07d2d0e93f6aaf7652a81e8df075fc1728da5e96

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Erlang · Erlang/OTPversion=17.0 <* changes=[{"at":"29.0.3","status":"unaffected"},{"at":"28.5.0.3","status":"unaffected"},{"at":"27.3.4.14","status":"unaffected"}]; version=5.3.4 <* changes=[{"at":"11.7.3","status":"unaffected"},{"at":"11.6.0.3","status":"unaffected"},{"at":"11.2.12.10","status":"unaffected"}]; version=84adefa331c4159d432d22840663c38f155cd4c1 <07d2d0e93f6aaf7652a81e8df075fc1728da5e96

Published CVSS scores

6.3Erlang Ecosystem FoundationCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
3.7NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-924Improper Enforcement of Message Integrity During Transmission in a Communication Channel
CAPEC-94Adversary in the Middle (AiTM)
T1557Adversary-in-the-Middle

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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