Amazon Linux 2027 Preview Security Advisory: ALAS2027-2026-013
Advisory Release Date: 2026-10-12 09:00 Pacific
Advisory Updated Date: 2026-10-20 15:48 Pacific
FAQs regarding Amazon Linux ALAS/CVE Severity
Package updates are available for Amazon Linux 2027 that fix the following vulnerabilities:
CVE-2026-91964:
FreeRDP versions before 3.31.0 contain a heap-based buffer overflow in nego_send_negotiation_request when processing Server Redirection PDU messages with attacker-controlled LoadBalanceInfo fields. A malicious RDP server can trigger the overflow by sending an arbitrary-length field that gets written to a fixed 512-byte buffer without validation, causing client crashes or potential code execution when chained with memory disclosure.
CVE-2026-91963:
FreeRDP versions before 3.31.0 contain an uninitialized heap memory disclosure vulnerability in the urbdrc USB redirection channel. A malicious RDP server can induce failing USB transfers to read uninitialized heap memory from the client, defeating ASLR and enabling remote code execution when chained with memory corruption vulnerabilities.
CVE-2026-91961:
FreeRDP before 3.31.0 contains a denial-of-service vulnerability in the URBDRC control-transfer request path that fails to validate OutputBufferSize before forwarding to the libusb backend. A malicious RDP server can send a control-transfer request with OutputBufferSize set to 65536, triggering a reachable assertion that terminates the client process.
CVE-2026-91960:
FreeRDP versions before 3.31.0 contain an integer overflow in WinPR's Stream_EnsureRemainingCapacity function that allows remote attackers to cause denial of service. A malicious RD Gateway peer can send a WebSocket Ping frame with a crafted 64-bit extended payload length to trigger integer wraparound, resulting in a double free that crashes the FreeRDP client during connection.
CVE-2026-91959:
FreeRDP before 3.31.0 contains a buffer over-read vulnerability in the rts_read_result function within the RPC gateway transport parser. Attackers can send a malicious BIND_ACK PDU with a truncated result entry to trigger an out-of-bounds read causing process abort.
CVE-2026-91958:
FreeRDP versions before 3.31.0 fail to validate MonitorIds array values when parsing RDP connection files, allowing unbounded array indexing in xf_detect_monitors. Attackers can craft a malicious RDP file with an out-of-range selectedmonitors value to trigger out-of-bounds heap read and write operations when opened in xfreerdp.
CVE-2026-91957:
FreeRDP before 3.31.0 contains a use-after-free vulnerability in the smartcard RDPDR device handler when worker thread creation fails after device registration. Attackers can trigger thread creation failure during channel setup to cause device pointer deallocation while devman retains a reference, leading to crash or code execution.
CVE-2026-91956:
FreeRDP before 3.31.0 contains an out-of-bounds read vulnerability in the URBDRC channel's func_get_ep_desc function that indexes interface arrays by position instead of protocol field InterfaceNumber. A malicious RDP server can send a crafted SELECT_CONFIGURATION message with permuted InterfaceNumber values to read past allocated heap memory and crash the client.
CVE-2026-91955:
FreeRDP before 3.31.0 fails to validate client-supplied DesktopWidth and DesktopHeight values during GCC negotiation, allowing remote attackers to crash the server. Attackers can send crafted RDP packets with zero or oversized dimensions to trigger division-by-zero or assertion failures in multifragment update capability calculations, terminating the server process.
CVE-2026-91954:
FreeRDP before 3.31.0 contains a null pointer dereference vulnerability in gdi_surface_bits when processing Surface Bits commands with NSCodec codec ID. A malicious RDP server can crash a FreeRDP client by sending a crafted Surface Bits command claiming to use NSCodec, even when the codec is disabled.
CVE-2026-91953:
FreeRDP versions before 3.31.0 contain a heap buffer overflow vulnerability in nego_send_negotiation_request() that fails to validate the LB_LOAD_BALANCE_INFO field length before writing to a fixed 512-byte buffer. A malicious RDP server or man-in-the-middle can send a Server Redirection PDU with an oversized LB_LOAD_BALANCE_INFO value to overflow the buffer with attacker-controlled content, causing denial of service or heap corruption before authentication completes.
CVE-2026-91952:
FreeRDP versions before 3.31.0 contain an infinite-loop denial of service in the pool_decode_rect function when decoding AVC444 metablocks with more region rectangles than preallocated worker array size. A malicious RDP server can send crafted AVC444 graphics updates causing the threaded decode path to loop indefinitely, consuming CPU and preventing normal client operation.
CVE-2026-91951:
FreeRDP versions before 3.31.0 contain an out-of-bounds write vulnerability in the urbdrc client channel's urb_send_current_frame_number_result() function. A malicious RDP server can send a crafted 28-byte USB redirection message to trigger a 4-byte write past the allocated 16-byte buffer, causing denial of service when verbose asserts are enabled.
CVE-2026-91950:
FreeRDP before 3.31.0 contains an out-of-bounds read vulnerability in the rdpdr_dump_packet function due to 32-bit unsigned integer wraparound in buffer bounds validation. A malicious RDP server can send a crafted RDPDR packet with computerNameLen set to 0xFFFFFFF0 to bypass bounds checks and trigger memory reads past the packet buffer, causing client crashes or heap disclosure in logs.
CVE-2026-91949:
FreeRDP server versions before 3.31.0 contain a protocol negotiation bypass vulnerability that allows unauthenticated attackers to establish RDSTLS connections despite server policy disabling them. Attackers can send incompatible protocol requests, receive negotiation failures, then complete TLS handshake and enter RDSTLS to bypass pre-authentication transport restrictions.
CVE-2026-91948:
FreeRDP versions before 3.31.0 contain an out-of-bounds write vulnerability in server-side static virtual channel handling when CHANNEL_OPTION_SHOW_PROTOCOL is enabled. Authenticated clients can queue oversized channel messages that cause buffer underflow and corrupt heap memory including live pointers, potentially enabling code execution.
CVE-2026-91947:
FreeRDP server versions before 3.31.0 contain a use-after-free vulnerability in the DRDYNVC parser that dereferences a channel pointer after releasing the synchronization lock. Authenticated clients can race AUDIN channel closure messages against DRDYNVC data parsing to trigger heap-use-after-free when accessing freed channel objects.
CVE-2026-91946:
FreeRDP versions before 3.31.0 contain an information disclosure vulnerability in the RDPGFX server's ResetGraphics PDU serializer that fails to initialize padding bytes in the fixed 340-byte wire format. Attackers can receive uninitialized heap memory including live pointers and GLib function addresses transmitted in the PDU, defeating heap ASLR and disclosing the GLib module base address.
CVE-2026-91945:
FreeRDP versions before 3.31.0 contain an out-of-bounds read vulnerability in smartcard response decoders that fail to validate ATR length fields against fixed inline arrays. Authenticated RDP clients can send oversized ATR lengths in PAKID_CORE_DEVICE_IOCOMPLETION responses to trigger reads past stack or heap objects, causing process termination.
CVE-2026-85090:
A flaw was found in FreeRDP. A heap out-of-bounds read vulnerability exists in the `general_ChromaV1ToYUV444` function during AVC444 chroma plane reconstruction. A remote attacker, acting as a malicious Remote Desktop Protocol (RDP) server, can exploit this by sending a specially crafted `RFX_AVC444_BITMAP_STREAM` with specific frame geometry. This can lead to an out-of-bounds memory read, potentially disclosing sensitive heap data to the client or causing a client crash, resulting in a denial of service.
CVE-2026-85089:
A flaw was found in FreeRDP. This vulnerability allows a remote attacker with low privileges to disclose sensitive information from the server or proxy process memory to a downstream client. This occurs because certain functions responsible for writing Save Session Info Protocol Data Units (PDUs) use Stream_Seek instead of Stream_Zero for reserved padding fields, leading to the transmission of uninitialized heap memory that may contain cleartext credentials from previous sessions.
Affected Packages:
freerdp
Issue Correction:
Run dnf update freerdp or dnf update --advisory ALAS2027-2026-013 to update your system.
aarch64:
freerdp-debugsource-3.31.0-1.amzn2027.aarch64
libwinpr-debuginfo-3.31.0-1.amzn2027.aarch64
freerdp-debuginfo-3.31.0-1.amzn2027.aarch64
freerdp-server-debuginfo-3.31.0-1.amzn2027.aarch64
libwinpr-devel-3.31.0-1.amzn2027.aarch64
freerdp-libs-debuginfo-3.31.0-1.amzn2027.aarch64
freerdp-devel-3.31.0-1.amzn2027.aarch64
freerdp-server-3.31.0-1.amzn2027.aarch64
freerdp-3.31.0-1.amzn2027.aarch64
libwinpr-3.31.0-1.amzn2027.aarch64
freerdp-libs-3.31.0-1.amzn2027.aarch64
src:
freerdp-3.31.0-1.amzn2027.src
x86_64:
freerdp-libs-debuginfo-3.31.0-1.amzn2027.x86_64
libwinpr-debuginfo-3.31.0-1.amzn2027.x86_64
freerdp-3.31.0-1.amzn2027.x86_64
freerdp-debugsource-3.31.0-1.amzn2027.x86_64
libwinpr-devel-3.31.0-1.amzn2027.x86_64
freerdp-server-3.31.0-1.amzn2027.x86_64
freerdp-debuginfo-3.31.0-1.amzn2027.x86_64
freerdp-server-debuginfo-3.31.0-1.amzn2027.x86_64
libwinpr-3.31.0-1.amzn2027.x86_64
freerdp-libs-3.31.0-1.amzn2027.x86_64
freerdp-devel-3.31.0-1.amzn2027.x86_64