CVE WatchJul 21, 2026

CVE-2026-9499

An out-of-bounds read (buffer over-read) vulnerability exists in QTextCodec::codecForName() in Qt. When the function is called with a QByteA

CVSS

—

No CVSS

EPSS

—

KEV

—

Exploit Today

0-100

Published: Jul 21, 2026 · Last modified: Jul 21, 2026 · CWE-125

EPSS · 30d

Not enough EPSS history yet.

Technical description

An out-of-bounds read (buffer over-read) vulnerability exists in QTextCodec::codecForName() in Qt. When the function is called with a QByteArray that is not NUL-terminated (for example, one created with QByteArray::fromRawData()), the codec-name matching routine reads past the end of the supplied buffer. In most cases this results in an incorrect text codec being selected; in the worst case, if the over-read reaches unmapped memory, the process crashes (denial of service). The over-read is bounded by the length of the longest codec-name candidate, and the out-of-bounds bytes are only compared internally against Qt's fixed list of codec names, so no data is disclosed to an attacker. Applications that do not pass non-NUL-terminated QByteArrays to QTextCodec::codecForName() are not exposed. The affected code resides in the Qt5Compat module from Qt 6.0.0 onward, and in Qt Core (qtbase) in Qt 4.x and Qt 5.x.

Official references

Related CVEs

CVECVSSEPSSKEVRExploitTitleMod.

CVE-2026-598423.7 LOW

—

——0A flaw was found in libssh. During server-side GSSAPI key exchange, a client-supplied Curve25519 public key shorter than the expected length is copied without proper length validation, leading to an out-of-bounds heap read. This could allow a remote unauthenticated attacker to disclose small amounts of server memory.6h CVE-2026-646099.1 CRI

—

——0Out-of-bounds read via sun.misc.Unsafe in Apache Fory. When out-of-band zero-copy deserialization is used, readAlignedVarUint() can read beyond the bounds of the underlying buffer. Out-of-band zero-copy deserialization is an opt-in feature; applications that do not use it are not affected. This issue affects Apache Fory (formerly Apache Fury): from 0.5.0 before 1.4.0. Versions before 0.11.0 were published under the Maven coordinates org.apache.fury:fury-core. Users are recommended to upgrade to version 1.4.0, which fixes the issue.4h CVE-2026-445106.5 MED

9.9%

——3Rsync is a file-copying tool that uses a delta-transfer algorithm to synchronize remote and local files. In versions prior to 3.4.3, the receiver-side out-of-bounds array read in rsync's recv_files() lets a malicious rsync server (or any peer acting in the sender role) deterministically crash any rsync client that pulls from it. The trigger is fully wire-protocol-level, requires no special options on the victim, and works for both rsync:// URLs and remote-shell pulls; since inc_recurse is the protocol-30+ default, any client doing a normal recursive pull against an attacker-controlled URL is exposed. A malicious server sets CF_INC_RECURSE, sends a flist whose first sorted entry is not the leading "." directory (causing parent_ndx to be set to -1), then sends a transfer record with ndx = 0 and an iflag omitting ITEM_TRANSFER, causing the receiver to read 8 bytes before the allocated pointer array and dereference the result in f_name(). The impact is crash-only: the out-of-bounds read lands in glibc mmap chunk metadata and dereferences to an unmapped low address, producing a SEGV that cannot be leveraged into an exploit (confirmed on glibc x86-64 Linux; non-glibc allocators not audited). This issue is fixed in version 3.4.3.20h CVE-2026-556395.3 MED

34.5%

——10xrdp is an open source RDP server. Versions 0.10.6 and prior contain a vulnerability concerning the parsing of Client Security Data within the Client MCS Connect Initial PDU with GCC Conference Create Request during the connection sequence. During the initial capability and security negotiation phase, the parser fails to perform sufficient length validation for the incoming data block. A remote, unauthenticated attacker could potentially exploit this flaw by sending a specially crafted RDP packet containing malformed data. Due to missing bounds checks, the xrdp process may read a small number of bytes beyond the declared data block boundary, potentially disclosing process memory contents that could be combined with other vulnerabilities. This issue has been fixed in version 0.10.6.1.23h CVE-2026-556456.5 MED

38.3%

——12xrdp is an open source RDP server. Versions 0.10.6 and prior contain a vulnerability concerning the processing of Client Control PDUs. During the RDP connection sequence, the parser does not perform sufficient length validation before reading specific data fields from the network stream. A remote, unauthenticated attacker could potentially exploit this flaw by sending a specially crafted, truncated Client Control PDU. Due to missing bounds checks, the xrdp process may perform out-of-bounds memory reads, which can result in the termination of the service (Denial of Service). However, since xrdp forks a new process for each connection by default, an out-of-bounds read causing a process crash is unlikely to bring down the entire xrdp service.This issue has been fixed in version 0.10.6.1.1d CVE-2026-449785.3 MED

41.5%

——12xrdp is an open source RDP server. Versions 0.10.6 and prior contain a heap out-of-bounds read vulnerability within the FIPS-specific receive paths. This vulnerability does not affect the default configuration of xrdp. The vulnerability is only exploitable when the security layer is set to security_layer=negotiate or security_layer=rdp, and the crypto level is changed to crypt_level=fips in xrdp.ini. In this specific non-default mode, the server fails to validate the FIPS padding length field, leading to a pointer underflow and a subsequent negative length calculation. An unauthenticated remote attacker can exploit this by sending a crafted FIPS-protected PDU, causing a heap out-of-bounds read that results in a process crash and denial of service (DoS). However, since xrdp forks a new process for each connection by default, an out-of-bounds read causing a process crash is unlikely to bring down the entire xrdp service. This issue has been fixed in version 0.10.6.1.1d