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Date: Mon, 4 Jul 2022 01:31:18 -0400
From: Demi Marie Obenour <>
To: Open Source Software Security <>
Subject: Denial of service in GnuPG

GnuPG is vulnerable to a denial of service attack when processing
crafted detached signatures and/or certificates.  By concatenating the
same signature to itself a very large number of times, and then wrapping
them in a compressed packet, I am able to cause GnuPG to take over a
minute to process an input that is less than 5KB armored. should fix this particular bug by refusing to
process compressed packets in detached signatures and/or certificates.
There may be further problems with non-detached signatures that are not
addressed by D556, but I recommend applying D556 first.

Signature (of /dev/null) that triggers this bug is attached, along with
the corresponding public key.
Demi Marie Obenour (she/her/hers)
Invisible Things Lab

Download attachment "test-key.cert" of type "application/octet-stream" (1209 bytes)

View attachment "decomp-3" of type "text/plain" (4604 bytes)

Download attachment "signature.asc" of type "application/pgp-signature" (834 bytes)

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