CyberSecBulletin
CVE-2026-55952NVD status: Modified

OTP: Improper Validation of Specified Quantity in Input

Published Updated By the CyberSecBulletin desk

CVE-2026-55952 is a high-severity improper validation of specified quantity in input vulnerability in OTP from Erlang, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected OTP versions: 22.2 and later; 9.5 and later; 339a279f02ce38a7b23010e56000613e19abb21f and later. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.55% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Erlang/otp to 27.3.4.14 or 28.5.0.3 or 29.0.3, whichever matches your release line, or a later version.
  2. Update Erlang/ssl to 11.2.12.10 or 11.6.0.3 or 11.7.3, whichever matches your release line, or a later version.
  3. Read the advisory on cna.erlef.org for workarounds and exact fixed builds.
  4. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
ErlangOTP22.2 and later; 9.5 and later; 339a279f02ce38a7b23010e56000613e19abb21f and laterNot stated
ErlangErlang/otp22.2 up to, but not including, 27.3.4.14; 28.0 up to, but not including, 28.5.0.3; 29.0 up to, but not including, 29.0.327.3.4.14, 28.5.0.3, 29.0.3
ErlangErlang/ssl9.5 up to, but not including, 11.2.12.10; 11.3 up to, but not including, 11.6.0.3; 11.7 up to, but not including, 11.7.311.2.12.10, 11.6.0.3, 11.7.3

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 4.08.2HighCNA
CVSS 3.17.5HighNVD

Official description

The Erlang/OTP ssl application does not validate that the PSK identity list and binder list carried in a TLS 1.3 ClientHello pre-shared key extension have equal length before passing them to the session ticket handler. In tls_handshake_1_3:handle_pre_shared_key/3, an OfferedPreSharedKeys record with a mismatched number of identities and binders is forwarded directly to tls_server_session_ticket:use/4, which crashes the session ticket handler process. An unauthenticated remote attacker can send a single crafted ClientHello to a TLS 1.3 server with session tickets enabled (stateful or stateless mode) and permanently disrupt session ticket handling on that listener. New TLS 1.3 handshakes complete but subsequently crash when the server attempts to issue a session ticket, effectively making TLS 1.3 unusable on the affected listener until the ssl application is restarted. TLS 1.2 connections are not affected. This issue affects OTP from OTP 22.2 before OTP 27.3.4.14, OTP 28.5.0.3, and OTP 29.0.3, corresponding to ssl from 9.5 before 11.2.12.10, 11.6.0.3, and 11.7.3.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Validation of Specified Quantity in Input

The product receives input that is expected to specify a quantity (such as size or length), but it does not validate or incorrectly validates that the quantity has the required properties.

More Improper Validation of Specified Quantity in Input vulnerabilities (CWE-1284)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in OTP

All OTP vulnerabilities

Recent Improper Validation of Specified Quantity in Input vulnerabilities

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