Vulnerabilities (CVE)

In GnuPG before 2.5.17, a crafted CMS (S/MIME) EnvelopedData message carrying an oversized wrapped session key can cause a stack-based buffer overflow in gpg-agent during PKDECRYPT--kem=CMS handling. This can easily be leveraged for denial of service; however, there is also memory corruption that could lead to remote code execution.

In GnuPG before 2.5.17, a long signature packet length causes parse_signature to return success with sig->data[] set to a NULL value, leading to a denial of service (application crash).

In GnuPG before 2.5.17, a stack-based buffer overflow exists in tpm2daemon during handling of the PKDECRYPT command for TPM-backed RSA and ECC keys.

In GnuPG before 2.4.9, armor_filter in g10/armor.c has two increments of an index variable where one is intended, leading to an out-of-bounds write for crafted input. (For ExtendedLTS, 2.2.51 and later are fixed versions.)

In GnuPG through 2.4.8, if a signed message has \f at the end of a plaintext line, an adversary can construct a modified message that places additional text after the signed material, such that signature verification of the modified message succeeds (although an "invalid armor" message is printed during verification). This is related to use of \f as a marker to denote truncation of a long plaintext line.

Libgcrypt before 1.8.8 and 1.9.x before 1.9.3 mishandles ElGamal encryption because it lacks exponent blinding to address a side-channel attack against mpi_powm, and the window size is not chosen appropriately. This, for example, affects use of ElGamal in OpenPGP.

In GnuPG before 2.5.5, if a user chooses to import a certificate with certain crafted subkey data that lacks a valid backsig or that has incorrect usage flags, the user loses the ability to verify signatures made from certain other signing keys, aka a "verification DoS."

The ElGamal implementation in Libgcrypt before 1.9.4 allows plaintext recovery because, during interaction between two cryptographic libraries, a certain dangerous combination of the prime defined by the receiver's public key, the generator defined by the receiver's public key, and the sender's ephemeral exponents can lead to a cross-configuration attack against OpenPGP.

In Libgcrypt before 1.7.7, an attacker who learns the EdDSA session key (from side-channel observation during the signing process) can easily recover the long-term secret key. 1.7.7 makes a cipher/ecc-eddsa.c change to store this session key in secure memory, to ensure that constant-time point operations are used in the MPI library.

Libgcrypt before 1.8.1 does not properly consider Curve25519 side-channel attacks, which makes it easier for attackers to discover a secret key, related to cipher/ecc.c and mpi/ec.c.

Libksba before 1.6.3 is prone to an integer overflow vulnerability in the CRL signature parser.

Integer underflow in the ksba_oid_to_str function in Libksba before 1.3.2, as used in GnuPG, allows remote attackers to cause a denial of service (crash) via a crafted OID in a (1) S/MIME message or (2) ECC based OpenPGP data, which triggers a buffer overflow.

Libgcrypt before 1.6.5 does not properly perform elliptic-point curve multiplication during decryption, which makes it easier for physically proximate attackers to extract ECDH keys by measuring electromagnetic emanations.

The mixing functions in the random number generator in Libgcrypt before 1.5.6, 1.6.x before 1.6.6, and 1.7.x before 1.7.3 and GnuPG before 1.4.21 make it easier for attackers to obtain the values of 160 bits by leveraging knowledge of the previous 4640 bits.

ber-decoder.c in Libksba before 1.3.3 uses an incorrect integer data type, which allows remote attackers to cause a denial of service (crash) via crafted BER data, which leads to a buffer overflow.

ber-decoder.c in Libksba before 1.3.3 does not properly handle decoder stack overflows, which allows remote attackers to cause a denial of service (abort) via crafted BER data.

Off-by-one error in the append_utf8_value function in the DN decoder (dn.c) in Libksba before 1.3.4 allows remote attackers to cause a denial of service (out-of-bounds read) via invalid utf-8 encoded data. NOTE: this vulnerability exists because of an incomplete fix for CVE-2016-4356.

Multiple integer overflows in ber-decoder.c in Libksba before 1.3.3 allow remote attackers to cause a denial of service (crash) via crafted BER data, which leads to a buffer overflow.

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.

Libgcrypt before 1.5.4, as used in GnuPG and other products, does not properly perform ciphertext normalization and ciphertext randomization, which makes it easier for physically proximate attackers to conduct key-extraction attacks by leveraging the ability to collect voltage data from exposed metal, a different vector than CVE-2013-4576.

Libksba before 1.3.4 allows remote attackers to cause a denial of service (out-of-bounds read and crash) via unspecified vectors, related to the "returned length of the object from _ksba_ber_parse_tl."

The append_utf8_value function in the DN decoder (dn.c) in Libksba before 1.3.3 allows remote attackers to cause a denial of service (out-of-bounds read) by clearing the high bit of the byte after invalid utf-8 encoded data.

The compressed packet parser in GnuPG 1.4.x before 1.4.15 and 2.0.x before 2.0.22 allows remote attackers to cause a denial of service (infinite recursion) via a crafted OpenPGP message.

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.

GnuPG 1.x before 1.4.16 generates RSA keys using sequences of introductions with certain patterns that introduce a side channel, which allows physically proximate attackers to extract RSA keys via a chosen-ciphertext attack and acoustic cryptanalysis during decryption. NOTE: applications are not typically expected to protect themselves from acoustic side-channel attacks, since this is arguably the responsibility of the physical device. Accordingly, issues of this type would not normally receive ... GnuPG 1.x before 1.4.16 generates RSA keys using sequences of introductions with certain patterns that introduce a side channel, which allows physically proximate attackers to extract RSA keys via a chosen-ciphertext attack and acoustic cryptanalysis during decryption. NOTE: applications are not typically expected to protect themselves from acoustic side-channel attacks, since this is arguably the responsibility of the physical device. Accordingly, issues of this type would not normally receive a CVE identifier. However, for this issue, the developer has specified a security policy in which GnuPG should offer side-channel resistance, and developer-specified security-policy violations are within the scope of CVE.

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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.

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.

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 1.4.6 and earlier and GPGME before 1.1.4, when run from the command line, does not visually distinguish signed and unsigned portions of OpenPGP messages with multiple components, which might allow remote attackers to forge the contents of a message without detection.

Heap-based buffer overflow in the ask_outfile_name function in openfile.c for GnuPG (gpg) 1.4 and 2.0, when running interactively, might allow attackers to execute arbitrary code via messages with "C-escape" expansions, which cause the make_printable_string function to return a longer string than expected while constructing a prompt.

GnuPG (gpg) 1.4.8 and 2.0.8 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via crafted duplicate keys that are imported from key servers, which triggers "memory corruption around deduplication of user IDs."

A vulnerability was found in the Libksba library due to an integer overflow within the CRL parser. The vulnerability can be exploited remotely for code execution on the target system by passing specially crafted data to the application, for example, a malicious S/MIME attachment.

The integrity check feature in OpenPGP, when handling a message that was encrypted using cipher feedback (CFB) mode, allows remote attackers to recover part of the plaintext via a chosen-ciphertext attack when the first 2 bytes of a message block are known, and an oracle or other mechanism is available to determine whether an integrity check failed.

Integer overflow in parse_comment in GnuPG (gpg) 1.4.4 allows remote attackers to cause a denial of service (segmentation fault) via a crafted message.

parse-packet.c in GnuPG (gpg) 1.4.3 and 1.9.20, and earlier versions, allows remote attackers to cause a denial of service (gpg crash) and possibly overwrite memory via a message packet with a large length (long user ID string), which could lead to an integer overflow, as demonstrated using the --no-armor option.

GnuPG can be made to spin on a relatively small input by (for example) crafting a public key with thousands of signatures attached, compressed down to just a few KB.

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.

_gcry_md_block_write in cipher/hash-common.c in Libgcrypt version 1.9.0 has a heap-based buffer overflow when the digest final function sets a large count value. It is recommended to upgrade to 1.9.1 or later.

GnuPG 2.2.21 and 2.2.22 (and Gpg4win 3.1.12) has an array overflow, leading to a crash or possibly unspecified other impact, when a victim imports an attacker's OpenPGP key, and this key has AEAD preferences. The overflow is caused by a g10/key-check.c error. NOTE: GnuPG 2.3.x is unaffected. GnuPG 2.2.23 is a fixed version.

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.