Is there a public exploit for CVE-2019-1543?

No public exploit for CVE-2019-1543 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

What does CVE-2019-1543 affect?

CVE-2019-1543 affects OpenSSL OpenSSL.

— Unscored

ChaCha20-Poly1305 is an AEAD cipher, and requires a unique nonce input for every encryption operation.

CVE-2019-1543

ChaCha20-Poly1305 is an AEAD cipher, and requires a unique nonce input for every encryption operation. RFC 7539 specifies that the nonce value (IV) should be 96 bits (12 bytes). OpenSSL allows a variable nonce length and front pads the nonce with 0 bytes if it is less than 12 bytes. However it also incorrectly allows a nonce to be set of up to 16 bytes. In this case only the last 12 bytes are significant and any additional leading bytes are ignored. It is a requirement of using this cipher that nonce values are unique. Messages encrypted using a reused nonce value are susceptible to serious confidentiality and integrity attacks. If an application changes the default nonce length to be longer than 12 bytes and then makes a change to the leading bytes of the nonce expecting the new value to be a new unique nonce then such an application could inadvertently encrypt messages with a reused nonce. Additionally the ignored bytes in a long nonce are not covered by the integrity guarantee of this cipher. Any application that relies on the integrity of these ignored leading bytes of a long nonce may be further affected. Any OpenSSL internal use of this cipher, including in SSL/TLS, is safe…

Assessment

CVSS: Not yet scored
Severity: Unscored
EPSS: 5.7% chance of exploitation in the next 30 days
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 6 March 2019
Last updated: 2 November 2026
Affected: OpenSSL · OpenSSL
Assigner: openssl

At the source

EUVD (ENISA)

References

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