As described in the announcement, this fixes a security issue:
There is one security fix in this release:
- Fix for a newly discovered security issue known as the 'Terrapin'
attack, also numbered CVE-2023-48795. The issue affects widely-used
OpenSSH extensions to the SSH protocol: the ChaCha20+Poly1305
cipher system, and 'encrypt-then-MAC' mode.
In order to benefit from the fix, you must be using a fixed version
of PuTTY _and_ a server with the fix, so that they can agree to
adopt a modified version of the protocol. Alternatively, you may be
able to reconfigure PuTTY to avoid selecting any of the affected
modes.
If PuTTY 0.80 connects to an SSH server without the fix, it will
warn you if the initial protocol negotiation chooses an insecure
mode to run the connection in, so that you can abandon the
connection. If it's possible to alter PuTTY's configuration to
avoid the problem, then the warning message will tell you how to do
it.
https://lists.tartarus.org/pipermail/putty-announce/2023/000037.html
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
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