What CVEs are caused by CWE-757?

30 recorded CVEs are attributed to CWE-757, including CVE-2026-72887, CVE-2017-9269, CVE-2026-55953.

What are the consequences of CWE-757?

Exploiting CWE-757 can lead to: Bypass Protection Mechanism.

Is CWE-757 actively exploited?

30 recorded CVEs are caused by CWE-757; none are currently in CISA's KEV catalog of actively exploited flaws.

RadicalNotion.AI

Log in Start free

Base weakness

Incomplete

CWE-757: Selection of Less-Secure Algorithm During Negotiation ('Algorithm Downgrade')

A protocol or its implementation supports interaction between multiple actors and allows those actors to negotiate which algorithm should be used as a protection mechanism such as encryption or authentication, but it does not select the strongest algorithm that is available to both parties.

Last updated May 1, 2026

30

Recorded CVEs

With this primary weakness

0

KEVs

In the CISA KEV catalog

Not rated

Likelihood of exploit

Per MITRE

Base

Abstraction

MITRE classification

Overview

When a security mechanism can be forced to downgrade to use a less secure algorithm, this can make it easier for attackers to compromise the product by exploiting weaker algorithm. The victim might not be aware that the less secure algorithm is being used. For example, if an attacker can force a communications channel to use cleartext instead of strongly-encrypted data, then the attacker could read the channel by sniffing, instead of going through extra effort of trying to decrypt the data using brute force techniques.

Real-world CVEs

30 recorded CVEs are caused by CWE-757 (Selection of Less-Secure Algorithm During Negotiation ('Algorithm Downgrade')). The highest-severity and most recent are shown first. 10 new CWE-757 CVEs have been recorded so far in 2026 (5 in 2025).

Showing 12 of 30 recorded CWE-757 CVEs. Track new ones as they are published and get AI-written analysis and fixes.

Monitor CWE-757 vulnerabilities

Common consequences

What can happen when CWE-757 is exploited.

Bypass Protection Mechanism

Affects: Access Control

How it happens

When it is introduced

Typically introduced during these phases of the software lifecycle.

Architecture and Design

How to detect it

Automated Static Analysis

Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

Effectiveness: High

Illustrative examples

Real CVEs that MITRE cites as examples of this weakness.

CVE-2006-4302 — Attacker can select an older version of the software to exploit its vulnerabilities.
CVE-2006-4407 — Improper prioritization of encryption ciphers during negotiation leads to use of a weaker cipher.
CVE-2005-2969 — chain: SSL/TLS implementation disables a verification step (CWE-325) that enables a downgrade attack to a weaker protocol.
CVE-2001-1444 — Telnet protocol implementation allows downgrade to weaker authentication and encryption using an Adversary-in-the-Middle AITM attack.
CVE-2002-1646 — SSH server implementation allows override of configuration setting to use weaker authentication schemes. This may be a composite with CWE-642.

Attack patterns

CAPEC attack patterns that exploit this weakness.

Frequently asked questions

Common questions about CWE-757.

What is CWE-757?: A protocol or its implementation supports interaction between multiple actors and allows those actors to negotiate which algorithm should be used as a protection mechanism such as encryption or authentication, but it does not select the strongest algorithm that is available to both parties.
What CVEs are caused by CWE-757?: 30 recorded CVEs are attributed to CWE-757, including CVE-2026-72887, CVE-2017-9269, CVE-2026-55953.
How is CWE-757 detected?: Automated Static Analysis: Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
What are the consequences of CWE-757?: Exploiting CWE-757 can lead to: Bypass Protection Mechanism.
Is CWE-757 actively exploited?: 30 recorded CVEs are caused by CWE-757; none are currently in CISA's KEV catalog of actively exploited flaws.

References

Weakness data is sourced from the MITRE CWE catalog (v4.20). CVE associations are aggregated and kept current by RadicalNotion.AI.

Stay ahead of CWE-757

Get alerted the moment a new CWE-757 vulnerability affects your stack, with AI-written analysis, severity context, and remediation guidance.

Start free See pricing