CVE WatchJul 20, 2026

CVE-2026-63091

ProFTPD before 1.3.9c and 1.3.10rc3 contains a signed integer overflow vulnerability in the mod_sftp module's SCP size-record parser that al

CVSS

6.5

Medium

EPSS

—

KEV

—

Exploit Today

0-100

Published: Jul 20, 2026 · Last modified: Jul 20, 2026 · CWE-126 · CWE-190

EPSS · 30d

Not enough EPSS history yet.

Technical description

ProFTPD before 1.3.9c and 1.3.10rc3 contains a signed integer overflow vulnerability in the mod_sftp module's SCP size-record parser that allows authenticated low-privilege attackers to bypass ASLR by sending a crafted file size value of UINT64_MAX, which results in a negative off_t value. Attackers can exploit the subsequent conversion to uint32_t, causing an approximately 4 GB requested read length and forcing the server to read beyond the end of the SSH channel data and write overread process memory into the uploaded file. In tested configurations, the disclosed data contains libc, libcrypto, and PIE pointers sufficient to derive their randomized base addresses, thereby bypassing ASLR and enabling reliable exploitation of memory corruption vulnerabilities in the same process.

Official references

Related CVEs

CVECVSSEPSSKEVRExploitTitleMod.

CVE-2026-445088.1 HIG

—

——0Rsync 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's compressed-token decoder accumulated a 32-bit signed counter without checking for overflow. A malicious sender can trigger an overflow that with careful manipulation can lead to the extraction of data stored in memory of the process allowing an attacker to access environment variables, passwords and memory pointers from the heap, stack, and libraries. The leakage of these pointers and data can significantly reduce the effectiveness of ASLR and facilitate further exploitation. This issue is fixed in version 3.4.3.16h CVE-2026-552385.3 MED

—

——0xrdp is an open source RDP server. Versions 0.10.6 and prior contain a vulnerability concerning the processing of RDP Confirm Active PDU, where during the capability negotiation phase, the parser did not perform sufficient length validation for specific capability sets. A remote, unauthenticated attacker could potentially exploit this flaw by sending a specially crafted RDP packet containing malformed capability data. 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 0.10.6.1.18h CVE-2026-415218.2 HIG

—

——0xrdp is an open source RDP server. Versions 0.10.6 and prior contain an integer overflow vulnerability when processing screen update messages within the vnc-any connection mode. A malicious remote VNC server can send crafted image dimensions that cause an integer overflow during memory buffer size calculation, resulting in an undersized allocation. Subsequent processing of the incoming image data using the original oversized parameters leads to an out-of-bounds read. An unauthenticated remote attacker could exploit this flaw to disclose sensitive information from the heap memory or cause a denial of service (DoS) via a process crash. This issue has been fixed in version 0.10.6.1.18h CVE-2026-33328—

—

——0libvips is a fast image processing library with low memory needs. On 32-bit systems in versions before and including 8.18.0, the `gifload` operation could incorrectly determine dimensions leading to an integer overflow. This has been patched in version 8.18.1.20h CVE-2026-33327—

—

——0libvips is a fast image processing library with low memory needs. The `vipsload` operation in versions before and including 8.18.0 could incorrectly determine image dimensions leading to an integer overflow and a subsequent heap-based buffer overflow. This has been patched in version 8.18.1.18h CVE-2026-552544.8 MED

8.7%

——3NCalc is a fast, lightweight expression evaluator for .NET. Prior to 6.1.1, the factorial operator implementation in src/NCalc.Core/Helpers/MathHelper.cs permits specially crafted expressions with extremely large factorial operands, causing excessive CPU consumption or a non-terminating loop due to integer overflow in the factorial calculation logic when applications evaluate untrusted expressions. This issue is fixed in version 6.1.1.18h