libreswan vulnerabilities

Null Pointer Dereference in PKCS#7 bundle with no certificates

Libreswan has a null pointer dereference bug in the PKCS#7 handling code for IKE certificate authentication. When libreswan decodes an IKE CERT payload of type CERT_PKCS7_WRAPPED_X509, it guards the PKCS#7 blob with SEC_PKCS7ContainsCertsOrCrls() and then iterates the certificate list with SEC_PKCS7GetCertificateList(). The two NSS APIs disagree on a SignedData that carries a CRL but no certificates: ContainsCertsOrCrls() returns PR_TRUE (there is a CRL), so the guard passes, but GetCertificateList() returns NULL (there are no certificates). This causes libreswan to dereference a null pointer leading to a crash and restart. A malicious IKE_AU

IKEv2 pre-authentication Null Pointer Dereference in EAP code

Libreswan's IKEv2 state machine has a null pointer dereference bug in the EAP handling code for authentication. As a result of inconsistency within the IKEv2 state machine code, this bug can be triggered by any IKEv2 connection, even if EAP is not configured at all. The error is caused by a fall-through where it incorrectly dereferences ike->sa.st_eap which is NULL. A malicious IKE_AUTH packet can trigger this bug, meaning the peer does not need to be authenticated. The bug results in a crash and restart of the pluto daemon. No remote code execution is possible. Continued exploitation can cause a denial of service.

Denial of Service via sending bogus X.509 certificates

Libreswan in FIPS mode has a vulnerability where badly formed received certificates are rejected, but not deleted from the NSS cache. As a result, any real certificates with the same serial number are rejected as well. This can be abused to lock out legitimate peers from connecting. The add_decoded_cert() function missed a call to CERT_DestroyCertificate() due to an incorrect fix for CVE-2026-14957. Sending bogus certificates with new serial numbers could prevent the real certificates with those serial numbers from connecting until the service has restarted.

IKEv2 Use-After-Free bug when using IKE-over-TCP

Libreswan's pluto daemon has a use-after-free vulnerability when a client connecting using IKE over TCP closes the connection and another packet (retransmit or malicious) is received for the same tuple. IKE state is retained in memory after the client closes the connection, storing a pointer to iface_endpoint inside ike_sa.sa->st_iface_endpoint. Once this invalid pointer is used, the daemon crashes and restarts. This vulnerability can be triggered before the remote peer has authenticated itself. Continued exploitation can lead to a denial of service. Remote code execution could be possible. The IKE over TCP option is not enabled by default; o

FIPS mode assertion failure via malicious CERT payload

In FIPS mode, Libreswan's add_decoded_cert() function calls CERT_ExtractPublicKey() and asserts that the result is not NULL. However, CERT_ExtractPublicKey() returns NULL when public key extraction fails, for example if the RSA exponent is set to 0. A remote attacker can send a malformed X.509 certificate in a CERT payload to trigger the assertion, causing the pluto daemon to abort and restart. Continued exploitation causes a denial of service. No remote code execution is possible. Both IKEv1 and IKEv2 are affected. The vulnerability is only exploitable when both the OS and libreswan are running in FIPS mode and at least one CA certificate is

• Update to 5.2-2.5

IKEv1 Denial of Service via RSA-SHA1 (PKCS#1 Version 1.5 Encrypted) authentication payload

Libreswan, via the function RSA_authenticate_hash_signature_raw_rsa(), did not correctly verify the length of the authentication hash when the SIG payload of an IKEv1 packet was encoded using PKCS #1 RSA Encryption as per RFC 2313. A remote attacker can use a variation on the Bleichenbacher attack to forge the SIG payload when small public exponents are being used (e.g., e=3), which could lead to impersonation. Additionally, a remote attacker, by encoding a shorter than expected hash in the SIG payload, could trigger an assertion leading to denial-of-service. The daemon aborts and restarts; continued exploitation causes sustained denial of se

• Update to 5.2-2.5

IKEv2 Denial of Service via RSA-SHA1 (PKCS#1 RSASSA-PKCS1-v1_5) authentication payload

Libreswan, via the function RSA_authenticate_hash_signature_pkcs1_1_5_rsa(), did not correctly verify the DER encoding of the ASN.1 digest when the IKEv2 AUTH payload was encoded using RSASSA-PKCS1-v1_5 (RFC 8017). A remote attacker can use a variation on the Bleichenbacher attack to forge the AUTH payload when small public exponents are used (e.g., e=3), leading to impersonation. Additionally, a remote attacker, by encoding a shorter than expected hash in the AUTH payload, could trigger an assertion leading to denial-of-service. The daemon aborts and restarts; continued exploitation causes sustained denial of service. Remote code execution i

• Update to 5.2-2.5

IKEv2 Denial of Service via malformed fragmentation

An invalidly formatted IKEv2 fragment causes the Libreswan pluto daemon to crash and restart. Continued exploitation would cause a denial of service. The function reassemble_v2_incoming_fragments() would ignore unknown outer payloads but still store these in a fixed size array msg_digest.digest[PAYLIMIT]. An off-by-one error in the assertion PASSERT(logger, md->digest_roof < elemsof(md->digest)) causes the daemon to abort. No remote code execution is possible. Any configuration that allows IKEv2 connections that do not set fragmentation=no are vulnerable. IKEv1 is not affected.

• Update to 5.2-2.5

IKEv1 default AH/ESP responder can cause libreswan to abort and restart

The Libreswan Project was notified of an issue causing libreswan to restart when using IKEv1 without specifying an esp= line. When the peer requests AES-GMAC, libreswan's default proposal handler causes an assertion failure and crashes and restarts. IKEv2 connections are not affected.

• Update to 4.15-1

IKEv2 misconfiguration can cause libreswan to abort and restart

The Libreswan Project was notified of an issue causing libreswan to restart under some IKEv2 retransmit scenarios when a connection is configured to use PreSharedKeys (authby=secret) and the connection cannot find a matching configured secret. When such a connection is automatically added on startup using the auto= keyword, it can cause repeated crashes leading to a Denial of Service.

• Update to 4.14-1

CVE-2023-38712

An issue was discovered in Libreswan 3.x and 4.x before 4.12. When an IKEv1 ISAKMP SA Informational Exchange packet contains a Delete/Notify payload followed by further Notifies that act on the ISAKMP SA, such as a duplicated Delete/Notify message, a NULL pointer dereference on the deleted state causes the pluto daemon to crash and restart.

• Update to 4.12-1

CVE-2023-38711

An issue was discovered in Libreswan before 4.12. When an IKEv1 Quick Mode connection configured with ID_IPV4_ADDR or ID_IPV6_ADDR receives an IDcr payload with ID_FQDN, a NULL pointer dereference causes a crash and restart of the pluto daemon. NOTE: the earliest affected version is 4.6.

• Update to 4.12-1

CVE-2023-38710

An issue was discovered in Libreswan before 4.12. When an IKEv2 Child SA REKEY packet contains an invalid IPsec protocol ID number of 0 or 1, an error notify INVALID_SPI is sent back. The notify payload's protocol ID is copied from the incoming packet, but the code that verifies outgoing packets fails an assertion that the protocol ID must be ESP (2) or AH(3) and causes the pluto daemon to crash and restart. NOTE: the earliest affected version is 3.20.

• Update to 4.12-1

CVE-2023-30570

pluto in Libreswan before 4.11 allows a denial of service (responder SPI mishandling and daemon crash) via unauthenticated IKEv1 Aggressive Mode packets. The earliest affected version is 3.28.

• Update to 4.11-1

CVE-2023-23009

Libreswan 4.9 allows remote attackers to cause a denial of service (assert failure and daemon restart) via crafted TS payload with an incorrect selector length.

• Update to 4.9-2

CVE-2022-23094

Libreswan 4.2 through 4.5 allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via a crafted IKEv1 packet because pluto/ikev1.c wrongly expects that a state object exists. This is fixed in 4.6.

• Update to 4.6-1

CVE-2020-1763

An out-of-bounds buffer read flaw was found in the pluto daemon of libreswan from versions 3.27 till 3.31 where, an unauthenticated attacker could use this flaw to crash libreswan by sending specially-crafted IKEv1 Informational Exchange packets. The daemon respawns after the crash.

• Update to 3.32-1

CVE-2019-10155

The Libreswan Project has found a vulnerability in the processing of IKEv1 informational exchange packets which are encrypted and integrity protected using the established IKE SA encryption and integrity keys, but as a receiver, the integrity check value was not verified. This issue affects versions before 3.29.

• Update to 3.27-6

CVE-2019-12312

In Libreswan 3.27 an assertion failure can lead to a pluto IKE daemon restart. An attacker can trigger a NULL pointer dereference by initiating an IKEv2 IKE_SA_INIT exchange, followed by a bogus INFORMATIONAL exchange instead of the normallly expected IKE_AUTH exchange. This affects send_v2N_spi_response_from_state() in programs/pluto/ikev2_send.c that will then trigger a NULL pointer dereference leading to a restart of libreswan.

• Update to 3.27-5

CVE-2018-5389

The Internet Key Exchange v1 main mode is vulnerable to offline dictionary or brute force attacks. Reusing a key pair across different versions and modes of IKE could lead to cross-protocol authentication bypasses. It is well known, that the aggressive mode of IKEv1 PSK is vulnerable to offline dictionary or brute force attacks. For the main mode, however, only an online attack against PSK authentication was thought to be feasible. This vulnerability could allow an attacker to recover a weak Pre-Shared Key or enable the impersonation of a victim host or network.