Amazon Linux 2 (EOS) Security Advisory: ALAS2-2026-3992
Advisory Released Date: 2026-10-12
Advisory Updated Date: 2026-10-12
FAQs regarding Amazon Linux ALAS/CVE Severity
Issue summary: A certificate with many nameRelativeToCRLIssuer CRL
distribution points causes disproportionate heap growth when OpenSSL caches
X.509 extensions.
Impact summary: Receiving a crafted certificate from a malicious peer can lead
to significant memory pressure and possible Denial of Service in clients or
in servers that solicit client certificates.
CWE: CWE-770: Allocation of Resources Without Limits or Throttling
Description: A certificate or a set of certificates that fits under the limit for
size of certificates accepted from the peer (~100 KiB) can result in allocation
of several hundred MiB of resident memory on the receiving side
during a normal TLS handshake. This may be enough to crash the client or
server, if multiple concurrent connections lead to similarly large memory
allocations.
The fix postpones processing of the CRL distribution points extensions in
certificates to the time when the processed value is required for CRL processing.
This avoids keeping large memory allocations for a long time when such
certificates are received.
FIPS impact: no
The affected code is outside the FIPS module boundary. (CVE-2026-35189)
Issue summary: The generic elliptic-curve scalar multiplication used for
ECDSA and SM2 signature operations with curves that do not have a dedicated
implementation leaks information about the secret nonce through timing.
Impact summary: An attacker able to measure signing times may learn
information about the per-signature secret nonce, which over many signatures
can, via a lattice / Hidden Number Problem attack, lead to recovery of the
private key.
CWE: CWE-208: Observable Timing Discrepancy
Description: The generic elliptic-curve scalar multiplication used for
curves that do not have a dedicated constant-time implementation pads the
secret scalar with non-constant-time BIGNUM operations, so the time taken
depends on the value of the secret scalar derived from the ECDSA and SM2 nonce.
The leak is very small; observing it requires a large number of
measurements. The effect is largest for curves whose group order lies
on a machine-word boundary, such as brainpoolP384r1.
Applications using ECDSA signing over the Brainpool and other generic prime
curves, and SM2 signing on platforms that use the generic implementation,
are vulnerable to this issue.
The NIST curves P-256, P-384 and P-521 use dedicated constant-time
implementations and are not affected.
FIPS Impact: no
The FIPS modules are not affected: the approved NIST curves used in the FIPS
provider have dedicated constant-time implementations and do not use the
affected code path. (CVE-2026-54872)
A flaw was found in OpenSSL. The Datagram Transport Layer Security (DTLS) retransmission mechanism fails to properly handle handshake message writes that are suspended before completion. A remote attacker could exploit this vulnerability during handshake message retransmission, causing OpenSSL to read past the message buffer or overwrite internal state required to resume writing. This issue can result in information disclosure through out-of-bounds memory reads or cause a Denial of Service (DoS) by crashing the process. (CVE-2026-84782)
Affected Packages:
openssl
Note:
This advisory is applicable to Amazon Linux 2 (AL2) Core repository. Visit this FAQ section for the difference between AL2 Core and AL2 Extras advisories.
Issue Correction:
Run yum update openssl or yum update --advisory ALAS2-2026-3992 to update your system.
aarch64:
openssl-1.0.2k-24.amzn2.0.23.aarch64
openssl-libs-1.0.2k-24.amzn2.0.23.aarch64
openssl-devel-1.0.2k-24.amzn2.0.23.aarch64
openssl-static-1.0.2k-24.amzn2.0.23.aarch64
openssl-perl-1.0.2k-24.amzn2.0.23.aarch64
openssl-debuginfo-1.0.2k-24.amzn2.0.23.aarch64
i686:
openssl-1.0.2k-24.amzn2.0.23.i686
openssl-libs-1.0.2k-24.amzn2.0.23.i686
openssl-devel-1.0.2k-24.amzn2.0.23.i686
openssl-static-1.0.2k-24.amzn2.0.23.i686
openssl-perl-1.0.2k-24.amzn2.0.23.i686
openssl-debuginfo-1.0.2k-24.amzn2.0.23.i686
src:
openssl-1.0.2k-24.amzn2.0.23.src
x86_64:
openssl-1.0.2k-24.amzn2.0.23.x86_64
openssl-libs-1.0.2k-24.amzn2.0.23.x86_64
openssl-devel-1.0.2k-24.amzn2.0.23.x86_64
openssl-static-1.0.2k-24.amzn2.0.23.x86_64
openssl-perl-1.0.2k-24.amzn2.0.23.x86_64
openssl-debuginfo-1.0.2k-24.amzn2.0.23.x86_64