CVE-2026-2968
Cryptographic Signature Bypass in Cesanta Mongoose Poly1305 Handler
Publication date: 2026-02-23
Last updated on: 2026-04-29
Assigner: VulDB
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| cesanta | mongoose | to 7.20 (inc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-347 | The product does not verify, or incorrectly verifies, the cryptographic signature for data. |
| CWE-345 | The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
CVE-2026-2968 is a vulnerability in Cesanta Mongoose up to version 7.20 that affects the function mg_chacha20_poly1305_decrypt in the file /src/tls_chacha20.c. This function is responsible for handling the Poly1305 Authentication Tag, which is part of the ChaCha20-Poly1305 AEAD cipher used for encryption and authentication.
The vulnerability causes improper verification of the cryptographic signature (Poly1305 authentication tag) during decryption. This means that the authentication guarantees provided by the cipher are bypassed, allowing an attacker to modify encrypted data without detection.
Because ChaCha20 is a stream cipher, this flaw enables a man-in-the-middle attacker to perform precise bit-flipping attacks on any TLS record, modifying encrypted data in transit at the byte level while the server accepts these tampered records as authentic.
The attack can be launched remotely, but it is characterized by high complexity and difficult exploitability. The vendor was contacted but did not respond or provide a fix.
How can this vulnerability impact me? :
[{'type': 'paragraph', 'content': "This vulnerability impacts the security of TLS connections using Cesanta Mongoose's built-in TLS implementation by allowing attackers to bypass authentication and integrity checks on encrypted data."}, {'type': 'paragraph', 'content': 'An attacker can perform man-in-the-middle bit-flipping attacks on encrypted TLS records, modifying data in transit without detection. This compromises data integrity and could lead to unauthorized data manipulation.'}, {'type': 'paragraph', 'content': 'Since the vulnerability does not require authentication and can be exploited remotely, it poses a risk to any system relying on the affected Mongoose versions for secure communications.'}, {'type': 'paragraph', 'content': 'The lack of vendor response and absence of mitigations means that affected users should consider replacing the vulnerable component to maintain secure communications.'}] [2, 3]
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
There are no specific detection commands or network/system detection methods provided for this vulnerability in the available resources.
What immediate steps should I take to mitigate this vulnerability?
Immediate mitigation steps are not provided by the vendor, and no known fixes or countermeasures exist.
It is recommended to consider replacing the affected Cesanta Mongoose component with an alternative product to avoid the vulnerability.