Vulnerabilidades do Red Hat Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On

A signed integer overflow vulnerability was found in GStreamer's VMnc decoder. A crafted VMnc stream with large cursor dimensions can overflow signed integer payload-size arithmetic, bypassing a length check and leading to out-of-bounds reads. A remote attacker could trick a user into opening a specially crafted VMnc file, potentially causing a crash or information disclosure.

A heap buffer overflow vulnerability was found in GStreamer's librfb (RFB/VNC client). The rectangle bounds check incorrectly validates area rather than individual dimensions, allowing a malicious VNC server to send a rectangle that extends beyond the framebuffer. A remote attacker could set up a malicious VNC server and trick a user into connecting, resulting in an out-of-bounds heap write that could lead to code execution or a crash.

A symlink following vulnerability was found in the ABRT post-create event handler scripts in libreport. Event scripts write output files using shell redirections without the O_NOFOLLOW flag. If the target file is replaced with a symlink, the shell process running as root follows the symlink and writes content to the symlink target, allowing arbitrary file overwrites on the system.

A race condition was found in the abrt-dbus D-Bus service's ChownProblemDir method. ChownProblemDir opens the dump directory with DD_OPEN_READONLY and calls dd_chown to change ownership of all files to the caller's uid, succeeding even while post-create event handlers hold a write lock. This allows an attacker to gain filesystem-level control of the dump directory while privileged event scripts are still running.

A time-of-check time-of-use (TOCTOU) race condition was found in the abrt-dbus D-Bus service's SetElement method. Between dump directory creation and post-create event execution, any local user can call SetElement to write arbitrary text files into the root-owned dump directory, bypassing package validation and allowing crashes of unpackaged binaries to survive post-create processing.

An integer overflow flaw was found in the SASL I/O layer of 389 Directory Server (389-ds-base). In sasl_io_start_packet(), adding sizeof(uint32_t) to a crafted SASL packet length prefix of 0xFFFFFFFC causes unsigned wraparound to zero, bypassing the nsslapd-maxsasliosize limit and leading to a heap buffer overflow of up to approximately 2 megabytes of attacker-controlled data. After a successful SASL bind with integrity protection (SSF > 0), a remote attacker can cause a Denial of Service (DoS) or achieve Remote Code Execution (RCE). In FreeIPA and Red Hat Identity Management deployments, any domain user with a valid Kerberos ticket, enrolled host, or service account can trigger this vulnerability over the network. This flaw is independent of CVE-2025-14905, which patched schema.c only and did not modify sasl_io.c.

A flaw was found in dracut. A remote attacker on the adjacent network can exploit this vulnerability by providing specially crafted DHCP (Dynamic Host Configuration Protocol) options, such as a malicious hostname, to a system using dracut's legacy DHCP path. These options are improperly handled and written into temporary shell scripts without proper escaping, leading to command injection. This allows the attacker to achieve root code execution within the initramfs, potentially compromising the system's boot and network behavior.

A local privilege escalation vulnerability was found in the ansible.posix authorized_key module. The module's keyfile() function uses os.chown() instead of os.lchown() and opens files without O_NOFOLLOW when managing SSH authorized keys. An unprivileged local user can pre-stage symbolic links in their ~/.ssh directory to redirect file ownership changes to arbitrary system paths when an operator runs the authorized_key task as root, leading to local privilege escalation.

A flaw was found in 389 Directory Server. The dereference control plugin does not check for allocation failure before using a BER structure, allowing an unauthenticated remote attacker to crash the LDAP server when the system is under memory pressure.

An out-of-bounds write flaw was found in the X.Org X server and Xwayland in DRIGetBuffers/DRIGetBuffersWithFormat. A client that requests multiple DRI2BufferBackLeft attachments and one DRI2BufferFrontLeft can trigger an out-of-bounds heap write. This may be used to crash the server, or for privilege escalation if the X server runs as root.

A use-after-free flaw was found in the X.Org X server and Xwayland in SyncChangeCounter(). A client that sets up multiple SyncCounters can trigger a use-after-free when destroying those counters via a second client connection while changing those counters. This may be used to crash the server, or for privilege escalation if the X server runs as root.

A use-after-free flaw was found in the X.Org X server and Xwayland in FreeCounter(). A client that sets up multiple SyncCounters and awaits on those triggers can trigger a use-after-free when destroying those counters via a second client connection. This may be used to crash the server, or for privilege escalation if the X server runs as root.

A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. _XkbSetMapChecks() declares a fixed-size stack buffer mapWidths[256] indexed by key type index. The helper function CheckKeyTypes() writes to this buffer at a client-controlled offset, allowing a stack buffer overflow. This may be used to crash the server, or for privilege escalation if the X server runs as root.

A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. The X server has multiple stack buffers sized XkbMaxShiftLevel * XkbNumKbdGroups but CheckKeyTypes() does not verify or clamp non-canonical key types to XkbMaxShiftLevel. A client can change key types to excessive shift levels and trigger stack overflows. This is caused by an incomplete fix of CVE-2025-26597. This may be used to crash the server, or for privilege escalation if the X server runs as root.

A use-after-free flaw was found in the X.Org X server and Xwayland in miSyncDestroyFence(). A client that sets up multiple fence triggers can trigger a use-after-free function pointer call. An attacker would connect to the X server to set up a fence and await that fence, then a second X connection destroys the fence, causing the use-after-free. This may be used to crash the server, or for privilege escalation if the X server runs as root.

A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. A mismatch between the X server and the libXfont2 library's maximum font name length can cause a stack buffer overflow during font alias resolution. The server allocates a 256 byte stack buffer but libXfont2's alias target name length is 1024 bytes. A font alias name between 257 and 1023 bytes causes the X server to copy that name into the undersized stack buffer without further checks. This may be used to crash the server, or for privilege escalation if the X server runs as root.

A flaw was found in Poppler's Splash backend. A remote attacker could exploit this vulnerability by crafting a malicious PDF file that, when rendered, triggers an integer overflow in the `tilingPatternFill` function. This overflow leads to an undersized heap memory allocation, allowing a subsequent out-of-bounds write. Successful exploitation could result in arbitrary code execution, information disclosure, or denial of service within the context of the application processing the PDF.