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TLS 1.0 Missing CBC Padding Check

Moderate
IngelaAndin published GHSA-ffrq-5rxw-xj5m Sep 11, 2025

Package

OTP

Affected versions

>= 17.0

Patched versions

17.5
ssl (OTP)
>= 5.3.4
6.0

Description

Impact

Does not properly check CBC padding bytes when terminating connections, which makes it easier for man-in-the-middle attackers to obtain cleartext data via a padding-oracle attack, a variant of CVE-2014-3566 (aka POODLE).

To be able to interop with Google servers a CBC padding check was removed and add back when the POODLE attack was discovered and the Google servers fixed.

Workarounds

Do not use TLS-1.0

Affected/Unaffected Versions

A version larger than or equal to one of the listed patched versions is unaffected; otherwise, a version that satisfies an expression listed under affected versions is affected, and if it does not, it is unaffected.

The documentation of the new OTP version scheme describes how versions should be compared. Note that versions used prior to OTP 17.0, when the new OTP version scheme was introduced, are never listed since it is not well defined how to compare those versions.

This particular vulnerability exist in versions older then OTP 17.0 but not prior to ssl application version 4.0.1

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

CVE ID

CVE-2015-2774

Weaknesses

Exposure of Sensitive Information to an Unauthorized Actor

The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. Learn more on MITRE.