CVE-2026-2968: Cesanta Mongoose Poly1305 Authentication Tag tls_chacha20.c mg_chacha20_poly1305_decrypt signature verification

Published Feb 23, 2026
·
Updated

A vulnerability was detected in Cesanta Mongoose up to 7.20. This impacts the function mgchacha20poly1305decrypt of the file /src/tlschacha20.c of the component Poly1305 Authentication Tag Handler. The manipulation results in improper verification of cryptographic signature. The attack may be launched remotely. This attack is characterized by high complexity. The exploitability is said to be difficult. The exploit is now public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

Affected Software

2 affected components
Cesanta/Mongoose<=7.20
Cesanta Mongoose<=7.20

Event History

Feb 23, 2026
CVE Published
via MITRE·03:02 AM
Data Sourced
via MITRE·03:02 AM
DescriptionSeverityWeakness
Data Sourced
via NVD·04:16 AM
DescriptionSeverityWeaknessAffected Software
Apr 10, 58134
Event
via FIRST·01:31 PM
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Frequently Asked Questions

1

What is the severity of CVE-2026-2968?

CVE-2026-2968 has a critical severity rating due to its impact on Poly1305 authentication tag signature verification, potentially allowing attackers to bypass security measures.

2

How do I fix CVE-2026-2968?

To fix CVE-2026-2968, upgrade Cesanta Mongoose to version 7.21 or later, which addresses the vulnerability in the mg_chacha20_poly1305_decrypt function.

3

What are the risks associated with CVE-2026-2968?

The risks associated with CVE-2026-2968 include unauthorized decryption of messages and potential exploitation by attackers to compromise data integrity.

4

Which versions of Cesanta Mongoose are affected by CVE-2026-2968?

CVE-2026-2968 affects all versions of Cesanta Mongoose up to and including 7.20.

5

How can I determine if my application is vulnerable to CVE-2026-2968?

You can determine if your application is vulnerable to CVE-2026-2968 by checking if it uses Cesanta Mongoose version 7.20 or earlier in its implementation.

Contact

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CVE-2026-2968 - Cesanta Mongoose Poly1305 Authentication Tag tls_chacha20.c mg_chacha20_poly1305_decrypt signature verification - SecAlerts