GnuPG through 2.3.6, in unusual situations where an attacker possesses any secret-key information from a victim's keyring and other constraints (e.g., use of GPGME) are met, allows signature forgery via injection into the status line.

A flaw was found in the way certificate signatures could be forged using collisions found in the SHA-1 algorithm. An attacker could use this weakness to create forged certificate signatures. This issue affects GnuPG versions before 2.2.18.

dirmngr before 2.1.0 improperly handles certain system calls, which allows remote attackers to cause a denial of service (DOS) via a specially-crafted certificate.

kbx/keybox-search.c in GnuPG before 1.4.19, 2.0.x before 2.0.27, and 2.1.x before 2.1.2 does not properly handle bitwise left-shifts, which allows remote attackers to cause a denial of service (invalid read operation) via a crafted keyring file, related to sign extensions and "memcpy with overlapping ranges."

The keyring DB in GnuPG before 2.1.2 does not properly handle invalid packets, which allows remote attackers to cause a denial of service (invalid read and use-after-free) via a crafted keyring file.

Interaction between the sks-keyserver code through 1.2.0 of the SKS keyserver network, and GnuPG through 2.2.16, makes it risky to have a GnuPG keyserver configuration line referring to a host on the SKS keyserver network. Retrieving data from this network may cause a persistent denial of service, because of a Certificate Spamming Attack.

mainproc.c in GnuPG before 2.2.8 mishandles the original filename during decryption and verification actions, which allows remote attackers to spoof the output that GnuPG sends on file descriptor 2 to other programs that use the "--status-fd 2" option. For example, the OpenPGP data might represent an original filename that contains line feed characters in conjunction with GOODSIG or VALIDSIG status codes.

The do_uncompress function in g10/compress.c in GnuPG 1.x before 1.4.17 and 2.x before 2.0.24 allows context-dependent attackers to cause a denial of service (infinite loop) via malformed compressed packets, as demonstrated by an a3 01 5b ff byte sequence.

GnuPG 1.4.x, 2.0.x, and 2.1.x treats a key flags subpacket with all bits cleared (no usage permitted) as if it has all bits set (all usage permitted), which might allow remote attackers to bypass intended cryptographic protection mechanisms by leveraging the subkey.

GnuPG before 1.4.14, and Libgcrypt before 1.5.3 as used in GnuPG 2.0.x and possibly other products, allows local users to obtain private RSA keys via a cache side-channel attack involving the L3 cache, aka Flush+Reload.

The read_block function in g10/import.c in GnuPG 1.4.x before 1.4.13 and 2.0.x through 2.0.19, when importing a key, allows remote attackers to corrupt the public keyring database or cause a denial of service (application crash) via a crafted length field of an OpenPGP packet.

Use-after-free vulnerability in kbx/keybox-blob.c in GPGSM in GnuPG 2.x through 2.0.16 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a certificate with a large number of Subject Alternate Names, which is not properly handled in a realloc operation when importing the certificate or verifying its signature.